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  • Making one value "special"

    - by SplashHit
    What is the "computer science" term for the practice of assigning a special meaning to one of a type's values. For example a numeric variable called "amount_to_transfer" where the special value "0" means "entire account balance" or a date value "spouse_date_of_birth" where "1/1/1800" means "unmarried". I happen to feel that this is quite a bad "smell", but I'd like to have a name for it, and if possible, some blog post or article about why it's bad and how to fix it.

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  • Will AJAX cause my site to have a high bounce % and hurt my search ratings?

    - by Cryo
    I'm building an art gallery website that updates its images via AJAX, for those who have javascript enabled, rather than request multiple page loads. I assume this will appear as though my site has a high bounce percentage. I understand that search engines will not be able to index dynamic content, but will such a misinterpreted bounce rate hurt my search engine ratings, even if I have many return visitors?

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  • @"%@ in Objective C?

    - by doo
    I was following a tut and found a line of code like @"%@ button pressed.". I'm pretty sure the relevant part is the %@, but is the first @ an escape sequence or what? Anyways, searching symbols doesn't go well in any search engine so I thought I'd ask. I think the %@ is like {0} in C#?

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  • [ASP.NET] <%# %> vs <%= %>

    - by Bart
    Hello I am wondering what is the difference between <%# ... % and <%= ... % and <%$ ... % ? I couldn't find anything abt it, cause it's impossible to find <%= in search engine;/ Does these constructions have name to look for it? Could you explain pls? Cheers

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  • How to rewrite a URL with %23 in it?

    - by Jan P.
    I have a (wordpress) blog where after commenting the users are redirected back to the page with an anchor to their comment. Should look like this: http://example.org/foo-bar/#comment-570630 But somehow I get a lot of 404 ins my logfiles for such URLs: http://example.org/foo-bar/%23comment-570630 Is there a way to write a .htaccess rewrite rule to fix this? Bonus question: Any idea why this happens and what I can do about it?

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  • Design by Contract with Microsoft .Net Code Contract

    - by Fredrik N
    I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract   Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null.   Pre- and Postconditions   When working with DbC we are specifying pre- and postconditions.  Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT.   There are two kinds of Queries, the Basic Queries  (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration.   Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count].   1. Separate Commands and Queries   When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack.   2. Separate basic queries from derived queries There are two different kinds of queries,  the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query.   3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries.   When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   4. For each command, write a postcondition that specifies the value of every basic query.   For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called)  plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle.   5. For every query and command, decide on a suitable precondition.   We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   6. Write invariants to define unchanging properties of objects.   The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract:   public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

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  • Table sorting & pagination with jQuery and Razor in ASP.NET MVC

    - by hajan
    Introduction jQuery enjoys living inside pages which are built on top of ASP.NET MVC Framework. The ASP.NET MVC is a place where things are organized very well and it is quite hard to make them dirty, especially because the pattern enforces you on purity (you can still make it dirty if you want so ;) ). We all know how easy is to build a HTML table with a header row, footer row and table rows showing some data. With ASP.NET MVC we can do this pretty easy, but, the result will be pure HTML table which only shows data, but does not includes sorting, pagination or some other advanced features that we were used to have in the ASP.NET WebForms GridView. Ok, there is the WebGrid MVC Helper, but what if we want to make something from pure table in our own clean style? In one of my recent projects, I’ve been using the jQuery tablesorter and tablesorter.pager plugins that go along. You don’t need to know jQuery to make this work… You need to know little CSS to create nice design for your table, but of course you can use mine from the demo… So, what you will see in this blog is how to attach this plugin to your pure html table and a div for pagination and make your table with advanced sorting and pagination features.   Demo Project Resources The resources I’m using for this demo project are shown in the following solution explorer window print screen: Content/images – folder that contains all the up/down arrow images, pagination buttons etc. You can freely replace them with your own, but keep the names the same if you don’t want to change anything in the CSS we will built later. Content/Site.css – The main css theme, where we will add the theme for our table too Controllers/HomeController.cs – The controller I’m using for this project Models/Person.cs – For this demo, I’m using Person.cs class Scripts – jquery-1.4.4.min.js, jquery.tablesorter.js, jquery.tablesorter.pager.js – required script to make the magic happens Views/Home/Index.cshtml – Index view (razor view engine) the other items are not important for the demo. ASP.NET MVC 1. Model In this demo I use only one Person class which defines Person entity with several properties. You can use your own model, maybe one which will access data from database or any other resource. Person.cs public class Person {     public string Name { get; set; }     public string Surname { get; set; }     public string Email { get; set; }     public int? Phone { get; set; }     public DateTime? DateAdded { get; set; }     public int? Age { get; set; }     public Person(string name, string surname, string email,         int? phone, DateTime? dateadded, int? age)     {         Name = name;         Surname = surname;         Email = email;         Phone = phone;         DateAdded = dateadded;         Age = age;     } } 2. View In our example, we have only one Index.chtml page where Razor View engine is used. Razor view engine is my favorite for ASP.NET MVC because it’s very intuitive, fluid and keeps your code clean. 3. Controller Since this is simple example with one page, we use one HomeController.cs where we have two methods, one of ActionResult type (Index) and another GetPeople() used to create and return list of people. HomeController.cs public class HomeController : Controller {     //     // GET: /Home/     public ActionResult Index()     {         ViewBag.People = GetPeople();         return View();     }     public List<Person> GetPeople()     {         List<Person> listPeople = new List<Person>();                  listPeople.Add(new Person("Hajan", "Selmani", "[email protected]", 070070070,DateTime.Now, 25));                     listPeople.Add(new Person("Straight", "Dean", "[email protected]", 123456789, DateTime.Now.AddDays(-5), 35));         listPeople.Add(new Person("Karsen", "Livia", "[email protected]", 46874651, DateTime.Now.AddDays(-2), 31));         listPeople.Add(new Person("Ringer", "Anne", "[email protected]", null, DateTime.Now, null));         listPeople.Add(new Person("O'Leary", "Michael", "[email protected]", 32424344, DateTime.Now, 44));         listPeople.Add(new Person("Gringlesby", "Anne", "[email protected]", null, DateTime.Now.AddDays(-9), 18));         listPeople.Add(new Person("Locksley", "Stearns", "[email protected]", 2135345, DateTime.Now, null));         listPeople.Add(new Person("DeFrance", "Michel", "[email protected]", 235325352, DateTime.Now.AddDays(-18), null));         listPeople.Add(new Person("White", "Johnson", null, null, DateTime.Now.AddDays(-22), 55));         listPeople.Add(new Person("Panteley", "Sylvia", null, 23233223, DateTime.Now.AddDays(-1), 32));         listPeople.Add(new Person("Blotchet-Halls", "Reginald", null, 323243423, DateTime.Now, 26));         listPeople.Add(new Person("Merr", "South", "[email protected]", 3232442, DateTime.Now.AddDays(-5), 85));         listPeople.Add(new Person("MacFeather", "Stearns", "[email protected]", null, DateTime.Now, null));         return listPeople;     } }   TABLE CSS/HTML DESIGN Now, lets start with the implementation. First of all, lets create the table structure and the main CSS. 1. HTML Structure @{     Layout = null;     } <!DOCTYPE html> <html> <head>     <title>ASP.NET & jQuery</title>     <!-- referencing styles, scripts and writing custom js scripts will go here --> </head> <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th> value </th>                 </tr>             </thead>             <tbody>                 <tr>                     <td>value</td>                 </tr>             </tbody>             <tfoot>                 <tr>                     <th> value </th>                 </tr>             </tfoot>         </table>         <div id="pager">                      </div>     </div> </body> </html> So, this is the main structure you need to create for each of your tables where you want to apply the functionality we will create. Of course the scripts are referenced once ;). As you see, our table has class tablesorter and also we have a div with id pager. In the next steps we will use both these to create the needed functionalities. The complete Index.cshtml coded to get the data from controller and display in the page is: <body>     <div>         <table class="tablesorter">             <thead>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </thead>             <tbody>                 @{                     foreach (var p in ViewBag.People)                     {                                 <tr>                         <td>@p.Name</td>                         <td>@p.Surname</td>                         <td>@p.Email</td>                         <td>@p.Phone</td>                         <td>@p.DateAdded</td>                     </tr>                     }                 }             </tbody>             <tfoot>                 <tr>                     <th>Name</th>                     <th>Surname</th>                     <th>Email</th>                     <th>Phone</th>                     <th>Date Added</th>                 </tr>             </tfoot>         </table>         <div id="pager" style="position: none;">             <form>             <img src="@Url.Content("~/Content/images/first.png")" class="first" />             <img src="@Url.Content("~/Content/images/prev.png")" class="prev" />             <input type="text" class="pagedisplay" />             <img src="@Url.Content("~/Content/images/next.png")" class="next" />             <img src="@Url.Content("~/Content/images/last.png")" class="last" />             <select class="pagesize">                 <option selected="selected" value="5">5</option>                 <option value="10">10</option>                 <option value="20">20</option>                 <option value="30">30</option>                 <option value="40">40</option>             </select>             </form>         </div>     </div> </body> So, mainly the structure is the same. I have added @Razor code to create table with data retrieved from the ViewBag.People which has been filled with data in the home controller. 2. CSS Design The CSS code I’ve created is: /* DEMO TABLE */ body {     font-size: 75%;     font-family: Verdana, Tahoma, Arial, "Helvetica Neue", Helvetica, Sans-Serif;     color: #232323;     background-color: #fff; } table { border-spacing:0; border:1px solid gray;} table.tablesorter thead tr .header {     background-image: url(images/bg.png);     background-repeat: no-repeat;     background-position: center right;     cursor: pointer; } table.tablesorter tbody td {     color: #3D3D3D;     padding: 4px;     background-color: #FFF;     vertical-align: top; } table.tablesorter tbody tr.odd td {     background-color:#F0F0F6; } table.tablesorter thead tr .headerSortUp {     background-image: url(images/asc.png); } table.tablesorter thead tr .headerSortDown {     background-image: url(images/desc.png); } table th { width:150px;            border:1px outset gray;            background-color:#3C78B5;            color:White;            cursor:pointer; } table thead th:hover { background-color:Yellow; color:Black;} table td { width:150px; border:1px solid gray;} PAGINATION AND SORTING Now, when everything is ready and we have the data, lets make pagination and sorting functionalities 1. jQuery Scripts referencing <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.tablesorter.pager.js")" type="text/javascript"></script> 2. jQuery Sorting and Pagination script   <script type="text/javascript">     $(function () {         $("table.tablesorter").tablesorter({ widthFixed: true, sortList: [[0, 0]] })         .tablesorterPager({ container: $("#pager"), size: $(".pagesize option:selected").val() });     }); </script> So, with only two lines of code, I’m using both tablesorter and tablesorterPager plugins, giving some options to both these. Options added: tablesorter - widthFixed: true – gives fixed width of the columns tablesorter - sortList[[0,0]] – An array of instructions for per-column sorting and direction in the format: [[columnIndex, sortDirection], ... ] where columnIndex is a zero-based index for your columns left-to-right and sortDirection is 0 for Ascending and 1 for Descending. A valid argument that sorts ascending first by column 1 and then column 2 looks like: [[0,0],[1,0]] (source: http://tablesorter.com/docs/) tablesorterPager – container: $(“#pager”) – tells the pager container, the div with id pager in our case. tablesorterPager – size: the default size of each page, where I get the default value selected, so if you put selected to any other of the options in your select list, you will have this number of rows as default per page for the table too. END RESULTS 1. Table once the page is loaded (default results per page is 5 and is automatically sorted by 1st column as sortList is specified) 2. Sorted by Phone Descending 3. Changed pagination to 10 items per page 4. Sorted by Phone and Name (use SHIFT to sort on multiple columns) 5. Sorted by Date Added 6. Page 3, 5 items per page   ADDITIONAL ENHANCEMENTS We can do additional enhancements to the table. We can make search for each column. I will cover this in one of my next blogs. Stay tuned. DEMO PROJECT You can download demo project source code from HERE.CONCLUSION Once you finish with the demo, run your page and open the source code. You will be amazed of the purity of your code.Working with pagination in client side can be very useful. One of the benefits is performance, but if you have thousands of rows in your tables, you will get opposite result when talking about performance. Hence, sometimes it is nice idea to make pagination on back-end. So, the compromise between both approaches would be best to combine both of them. I use at most up to 500 rows on client-side and once the user reach the last page, we can trigger ajax postback which can get the next 500 rows using server-side pagination of the same data. I would like to recommend the following blog post http://weblogs.asp.net/gunnarpeipman/archive/2010/09/14/returning-paged-results-from-repositories-using-pagedresult-lt-t-gt.aspx, which will help you understand how to return page results from repository. I hope this was helpful post for you. Wait for my next posts ;). Please do let me know your feedback. Best Regards, Hajan

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  • SQL Server 2012 - AlwaysOn

    - by Claus Jandausch
    Ich war nicht nur irritiert, ich war sogar regelrecht schockiert - und für einen kurzen Moment sprachlos (was nur selten der Fall ist). Gerade eben hatte mich jemand gefragt "Wann Oracle denn etwas Vergleichbares wie AlwaysOn bieten würde - und ob überhaupt?" War ich hier im falschen Film gelandet? Ich konnte nicht anders, als meinen Unmut kundzutun und zu erklären, dass die Fragestellung normalerweise anders herum läuft. Zugegeben - es mag vielleicht strittige Punkte geben im Vergleich zwischen Oracle und SQL Server - bei denen nicht unbedingt immer Oracle die Nase vorn haben muss - aber das Thema Clustering für Hochverfügbarkeit (HA), Disaster Recovery (DR) und Skalierbarkeit gehört mit Sicherheit nicht dazu. Dieses Erlebnis hakte ich am Nachgang als Einzelfall ab, der so nie wieder vorkommen würde. Bis ich kurz darauf eines Besseren belehrt wurde und genau die selbe Frage erneut zu hören bekam. Diesmal sogar im Exadata-Umfeld und einem Oracle Stretch Cluster. Einmal ist keinmal, doch zweimal ist einmal zu viel... Getreu diesem alten Motto war mir klar, dass man das so nicht länger stehen lassen konnte. Ich habe keine Ahnung, wie die Microsoft Marketing Abteilung es geschafft hat, unter dem AlwaysOn Brading eine innovative Technologie vermuten zu lassen - aber sie hat ihren Job scheinbar gut gemacht. Doch abgesehen von einem guten Marketing, stellt sich natürlich die Frage, was wirklich dahinter steckt und wie sich das Ganze mit Oracle vergleichen lässt - und ob überhaupt? Damit wären wir wieder bei der ursprünglichen Frage angelangt.  So viel zum Hintergrund dieses Blogbeitrags - von meiner Antwort handelt der restliche Blog. "Windows was the God ..." Um den wahren Unterschied zwischen Oracle und Microsoft verstehen zu können, muss man zunächst das bedeutendste Microsoft Dogma kennen. Es lässt sich schlicht und einfach auf den Punkt bringen: "Alles muss auf Windows basieren." Die Überschrift dieses Absatzes ist kein von mir erfundener Ausspruch, sondern ein Zitat. Konkret stammt es aus einem längeren Artikel von Kurt Eichenwald in der Vanity Fair aus dem August 2012. Er lautet Microsoft's Lost Decade und sei jedem ans Herz gelegt, der die "Microsoft-Maschinerie" unter Steve Ballmer und einige ihrer Kuriositäten besser verstehen möchte. "YOU TALKING TO ME?" Microsoft C.E.O. Steve Ballmer bei seiner Keynote auf der 2012 International Consumer Electronics Show in Las Vegas am 9. Januar   Manche Dinge in diesem Artikel mögen überspitzt dargestellt erscheinen - sind sie aber nicht. Vieles davon kannte ich bereits aus eigener Erfahrung und kann es nur bestätigen. Anderes hat sich mir erst so richtig erschlossen. Insbesondere die folgenden Passagen führten zum Aha-Erlebnis: “Windows was the god—everything had to work with Windows,” said Stone... “Every little thing you want to write has to build off of Windows (or other existing roducts),” one software engineer said. “It can be very confusing, …” Ich habe immer schon darauf hingewiesen, dass in einem SQL Server Failover Cluster die Microsoft Datenbank eigentlich nichts Nenneswertes zum Geschehen beiträgt, sondern sich voll und ganz auf das Windows Betriebssystem verlässt. Deshalb muss man auch die Windows Server Enterprise Edition installieren, soll ein Failover Cluster für den SQL Server eingerichtet werden. Denn hier werden die Cluster Services geliefert - nicht mit dem SQL Server. Er ist nur lediglich ein weiteres Server Produkt, für das Windows in Ausfallszenarien genutzt werden kann - so wie Microsoft Exchange beispielsweise, oder Microsoft SharePoint, oder irgendein anderes Server Produkt das auf Windows gehostet wird. Auch Oracle kann damit genutzt werden. Das Stichwort lautet hier: Oracle Failsafe. Nur - warum sollte man das tun, wenn gleichzeitig eine überlegene Technologie wie die Oracle Real Application Clusters (RAC) zur Verfügung steht, die dann auch keine Windows Enterprise Edition voraussetzen, da Oracle die eigene Clusterware liefert. Welche darüber hinaus für kürzere Failover-Zeiten sorgt, da diese Cluster-Technologie Datenbank-integriert ist und sich nicht auf "Dritte" verlässt. Wenn man sich also schon keine technischen Vorteile mit einem SQL Server Failover Cluster erkauft, sondern zusätzlich noch versteckte Lizenzkosten durch die Lizenzierung der Windows Server Enterprise Edition einhandelt, warum hat Microsoft dann in den vergangenen Jahren seit SQL Server 2000 nicht ebenfalls an einer neuen und innovativen Lösung gearbeitet, die mit Oracle RAC mithalten kann? Entwickler hat Microsoft genügend? Am Geld kann es auch nicht liegen? Lesen Sie einfach noch einmal die beiden obenstehenden Zitate und sie werden den Grund verstehen. Anders lässt es sich ja auch gar nicht mehr erklären, dass AlwaysOn aus zwei unterschiedlichen Technologien besteht, die beide jedoch wiederum auf dem Windows Server Failover Clustering (WSFC) basieren. Denn daraus ergeben sich klare Nachteile - aber dazu später mehr. Um AlwaysOn zu verstehen, sollte man sich zunächst kurz in Erinnerung rufen, was Microsoft bisher an HA/DR (High Availability/Desaster Recovery) Lösungen für SQL Server zur Verfügung gestellt hat. Replikation Basiert auf logischer Replikation und Pubisher/Subscriber Architektur Transactional Replication Merge Replication Snapshot Replication Microsoft's Replikation ist vergleichbar mit Oracle GoldenGate. Oracle GoldenGate stellt jedoch die umfassendere Technologie dar und bietet High Performance. Log Shipping Microsoft's Log Shipping stellt eine einfache Technologie dar, die vergleichbar ist mit Oracle Managed Recovery in Oracle Version 7. Das Log Shipping besitzt folgende Merkmale: Transaction Log Backups werden von Primary nach Secondary/ies geschickt Einarbeitung (z.B. Restore) auf jedem Secondary individuell Optionale dritte Server Instanz (Monitor Server) für Überwachung und Alarm Log Restore Unterbrechung möglich für Read-Only Modus (Secondary) Keine Unterstützung von Automatic Failover Database Mirroring Microsoft's Database Mirroring wurde verfügbar mit SQL Server 2005, sah aus wie Oracle Data Guard in Oracle 9i, war funktional jedoch nicht so umfassend. Für ein HA/DR Paar besteht eine 1:1 Beziehung, um die produktive Datenbank (Principle DB) abzusichern. Auf der Standby Datenbank (Mirrored DB) werden alle Insert-, Update- und Delete-Operationen nachgezogen. Modi Synchron (High-Safety Modus) Asynchron (High-Performance Modus) Automatic Failover Unterstützt im High-Safety Modus (synchron) Witness Server vorausgesetzt     Zur Frage der Kontinuität Es stellt sich die Frage, wie es um diesen Technologien nun im Zusammenhang mit SQL Server 2012 bestellt ist. Unter Fanfaren seinerzeit eingeführt, war Database Mirroring das erklärte Mittel der Wahl. Ich bin kein Produkt Manager bei Microsoft und kann hierzu nur meine Meinung äußern, aber zieht man den SQL AlwaysOn Team Blog heran, so sieht es nicht gut aus für das Database Mirroring - zumindest nicht langfristig. "Does AlwaysOn Availability Group replace Database Mirroring going forward?” “The short answer is we recommend that you migrate from the mirroring configuration or even mirroring and log shipping configuration to using Availability Group. Database Mirroring will still be available in the Denali release but will be phased out over subsequent releases. Log Shipping will continue to be available in future releases.” Damit wären wir endlich beim eigentlichen Thema angelangt. Was ist eine sogenannte Availability Group und was genau hat es mit der vielversprechend klingenden Bezeichnung AlwaysOn auf sich?   SQL Server 2012 - AlwaysOn Zwei HA-Features verstekcne sich hinter dem “AlwaysOn”-Branding. Einmal das AlwaysOn Failover Clustering aka SQL Server Failover Cluster Instances (FCI) - zum Anderen die AlwaysOn Availability Groups. Failover Cluster Instances (FCI) Entspricht ungefähr dem Stretch Cluster Konzept von Oracle Setzt auf Windows Server Failover Clustering (WSFC) auf Bietet HA auf Instanz-Ebene AlwaysOn Availability Groups (Verfügbarkeitsgruppen) Ähnlich der Idee von Consistency Groups, wie in Storage-Level Replikations-Software von z.B. EMC SRDF Abhängigkeiten zu Windows Server Failover Clustering (WSFC) Bietet HA auf Datenbank-Ebene   Hinweis: Verwechseln Sie nicht eine SQL Server Datenbank mit einer Oracle Datenbank. Und auch nicht eine Oracle Instanz mit einer SQL Server Instanz. Die gleichen Begriffe haben hier eine andere Bedeutung - nicht selten ein Grund, weshalb Oracle- und Microsoft DBAs schnell aneinander vorbei reden. Denken Sie bei einer SQL Server Datenbank eher an ein Oracle Schema, das kommt der Sache näher. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema. Wenn Sie die genauen Unterschiede kennen möchten, finden Sie eine detaillierte Beschreibung in meinem Buch "Oracle10g Release 2 für Windows und .NET", erhältich bei Lehmanns, Amazon, etc.   Windows Server Failover Clustering (WSFC) Wie man sieht, basieren beide AlwaysOn Technologien wiederum auf dem Windows Server Failover Clustering (WSFC), um einerseits Hochverfügbarkeit auf Ebene der Instanz zu gewährleisten und andererseits auf der Datenbank-Ebene. Deshalb nun eine kurze Beschreibung der WSFC. Die WSFC sind ein mit dem Windows Betriebssystem geliefertes Infrastruktur-Feature, um HA für Server Anwendungen, wie Microsoft Exchange, SharePoint, SQL Server, etc. zu bieten. So wie jeder andere Cluster, besteht ein WSFC Cluster aus einer Gruppe unabhängiger Server, die zusammenarbeiten, um die Verfügbarkeit einer Applikation oder eines Service zu erhöhen. Falls ein Cluster-Knoten oder -Service ausfällt, kann der auf diesem Knoten bisher gehostete Service automatisch oder manuell auf einen anderen im Cluster verfügbaren Knoten transferriert werden - was allgemein als Failover bekannt ist. Unter SQL Server 2012 verwenden sowohl die AlwaysOn Avalability Groups, als auch die AlwaysOn Failover Cluster Instances die WSFC als Plattformtechnologie, um Komponenten als WSFC Cluster-Ressourcen zu registrieren. Verwandte Ressourcen werden in eine Ressource Group zusammengefasst, die in Abhängigkeit zu anderen WSFC Cluster-Ressourcen gebracht werden kann. Der WSFC Cluster Service kann jetzt die Notwendigkeit zum Neustart der SQL Server Instanz erfassen oder einen automatischen Failover zu einem anderen Server-Knoten im WSFC Cluster auslösen.   Failover Cluster Instances (FCI) Eine SQL Server Failover Cluster Instanz (FCI) ist eine einzelne SQL Server Instanz, die in einem Failover Cluster betrieben wird, der aus mehreren Windows Server Failover Clustering (WSFC) Knoten besteht und so HA (High Availability) auf Ebene der Instanz bietet. Unter Verwendung von Multi-Subnet FCI kann auch Remote DR (Disaster Recovery) unterstützt werden. Eine weitere Option für Remote DR besteht darin, eine unter FCI gehostete Datenbank in einer Availability Group zu betreiben. Hierzu später mehr. FCI und WSFC Basis FCI, das für lokale Hochverfügbarkeit der Instanzen genutzt wird, ähnelt der veralteten Architektur eines kalten Cluster (Aktiv-Passiv). Unter SQL Server 2008 wurde diese Technologie SQL Server 2008 Failover Clustering genannt. Sie nutzte den Windows Server Failover Cluster. In SQL Server 2012 hat Microsoft diese Basistechnologie unter der Bezeichnung AlwaysOn zusammengefasst. Es handelt sich aber nach wie vor um die klassische Aktiv-Passiv-Konfiguration. Der Ablauf im Failover-Fall ist wie folgt: Solange kein Hardware-oder System-Fehler auftritt, werden alle Dirty Pages im Buffer Cache auf Platte geschrieben Alle entsprechenden SQL Server Services (Dienste) in der Ressource Gruppe werden auf dem aktiven Knoten gestoppt Die Ownership der Ressource Gruppe wird auf einen anderen Knoten der FCI transferriert Der neue Owner (Besitzer) der Ressource Gruppe startet seine SQL Server Services (Dienste) Die Connection-Anforderungen einer Client-Applikation werden automatisch auf den neuen aktiven Knoten mit dem selben Virtuellen Network Namen (VNN) umgeleitet Abhängig vom Zeitpunkt des letzten Checkpoints, kann die Anzahl der Dirty Pages im Buffer Cache, die noch auf Platte geschrieben werden müssen, zu unvorhersehbar langen Failover-Zeiten führen. Um diese Anzahl zu drosseln, besitzt der SQL Server 2012 eine neue Fähigkeit, die Indirect Checkpoints genannt wird. Indirect Checkpoints ähnelt dem Fast-Start MTTR Target Feature der Oracle Datenbank, das bereits mit Oracle9i verfügbar war.   SQL Server Multi-Subnet Clustering Ein SQL Server Multi-Subnet Failover Cluster entspricht vom Konzept her einem Oracle RAC Stretch Cluster. Doch dies ist nur auf den ersten Blick der Fall. Im Gegensatz zu RAC ist in einem lokalen SQL Server Failover Cluster jeweils nur ein Knoten aktiv für eine Datenbank. Für die Datenreplikation zwischen geografisch entfernten Sites verlässt sich Microsoft auf 3rd Party Lösungen für das Storage Mirroring.     Die Verbesserung dieses Szenario mit einer SQL Server 2012 Implementierung besteht schlicht darin, dass eine VLAN-Konfiguration (Virtual Local Area Network) nun nicht mehr benötigt wird, so wie dies bisher der Fall war. Das folgende Diagramm stellt dar, wie der Ablauf mit SQL Server 2012 gehandhabt wird. In Site A und Site B wird HA jeweils durch einen lokalen Aktiv-Passiv-Cluster sichergestellt.     Besondere Aufmerksamkeit muss hier der Konfiguration und dem Tuning geschenkt werden, da ansonsten völlig inakzeptable Failover-Zeiten resultieren. Dies liegt darin begründet, weil die Downtime auf Client-Seite nun nicht mehr nur von der reinen Failover-Zeit abhängt, sondern zusätzlich von der Dauer der DNS Replikation zwischen den DNS Servern. (Rufen Sie sich in Erinnerung, dass wir gerade von Multi-Subnet Clustering sprechen). Außerdem ist zu berücksichtigen, wie schnell die Clients die aktualisierten DNS Informationen abfragen. Spezielle Konfigurationen für Node Heartbeat, HostRecordTTL (Host Record Time-to-Live) und Intersite Replication Frequeny für Active Directory Sites und Services werden notwendig. Default TTL für Windows Server 2008 R2: 20 Minuten Empfohlene Einstellung: 1 Minute DNS Update Replication Frequency in Windows Umgebung: 180 Minuten Empfohlene Einstellung: 15 Minuten (minimaler Wert)   Betrachtet man diese Werte, muss man feststellen, dass selbst eine optimale Konfiguration die rigiden SLAs (Service Level Agreements) heutiger geschäftskritischer Anwendungen für HA und DR nicht erfüllen kann. Denn dies impliziert eine auf der Client-Seite erlebte Failover-Zeit von insgesamt 16 Minuten. Hierzu ein Auszug aus der SQL Server 2012 Online Dokumentation: Cons: If a cross-subnet failover occurs, the client recovery time could be 15 minutes or longer, depending on your HostRecordTTL setting and the setting of your cross-site DNS/AD replication schedule.    Wir sind hier an einem Punkt unserer Überlegungen angelangt, an dem sich erklärt, weshalb ich zuvor das "Windows was the God ..." Zitat verwendet habe. Die unbedingte Abhängigkeit zu Windows wird zunehmend zum Problem, da sie die Komplexität einer Microsoft-basierenden Lösung erhöht, anstelle sie zu reduzieren. Und Komplexität ist das Letzte, was sich CIOs heutzutage wünschen.  Zur Ehrenrettung des SQL Server 2012 und AlwaysOn muss man sagen, dass derart lange Failover-Zeiten kein unbedingtes "Muss" darstellen, sondern ein "Kann". Doch auch ein "Kann" kann im unpassenden Moment unvorhersehbare und kostspielige Folgen haben. Die Unabsehbarkeit ist wiederum Ursache vieler an der Implementierung beteiligten Komponenten und deren Abhängigkeiten, wie beispielsweise drei Cluster-Lösungen (zwei von Microsoft, eine 3rd Party Lösung). Wie man die Sache auch dreht und wendet, kommt man an diesem Fakt also nicht vorbei - ganz unabhängig von der Dauer einer Downtime oder Failover-Zeiten. Im Gegensatz zu AlwaysOn und der hier vorgestellten Version eines Stretch-Clusters, vermeidet eine entsprechende Oracle Implementierung eine derartige Komplexität, hervorgerufen duch multiple Abhängigkeiten. Den Unterschied machen Datenbank-integrierte Mechanismen, wie Fast Application Notification (FAN) und Fast Connection Failover (FCF). Für Oracle MAA Konfigurationen (Maximum Availability Architecture) sind Inter-Site Failover-Zeiten im Bereich von Sekunden keine Seltenheit. Wenn Sie dem Link zur Oracle MAA folgen, finden Sie außerdem eine Reihe an Customer Case Studies. Auch dies ist ein wichtiges Unterscheidungsmerkmal zu AlwaysOn, denn die Oracle Technologie hat sich bereits zigfach in höchst kritischen Umgebungen bewährt.   Availability Groups (Verfügbarkeitsgruppen) Die sogenannten Availability Groups (Verfügbarkeitsgruppen) sind - neben FCI - der weitere Baustein von AlwaysOn.   Hinweis: Bevor wir uns näher damit beschäftigen, sollten Sie sich noch einmal ins Gedächtnis rufen, dass eine SQL Server Datenbank nicht die gleiche Bedeutung besitzt, wie eine Oracle Datenbank, sondern eher einem Oracle Schema entspricht. So etwas wie die SQL Server Northwind Datenbank ist vergleichbar mit dem Oracle Scott Schema.   Eine Verfügbarkeitsgruppe setzt sich zusammen aus einem Set mehrerer Benutzer-Datenbanken, die im Falle eines Failover gemeinsam als Gruppe behandelt werden. Eine Verfügbarkeitsgruppe unterstützt ein Set an primären Datenbanken (primäres Replikat) und einem bis vier Sets von entsprechenden sekundären Datenbanken (sekundäre Replikate).       Es können jedoch nicht alle SQL Server Datenbanken einer AlwaysOn Verfügbarkeitsgruppe zugeordnet werden. Der SQL Server Spezialist Michael Otey zählt in seinem SQL Server Pro Artikel folgende Anforderungen auf: Verfügbarkeitsgruppen müssen mit Benutzer-Datenbanken erstellt werden. System-Datenbanken können nicht verwendet werden Die Datenbanken müssen sich im Read-Write Modus befinden. Read-Only Datenbanken werden nicht unterstützt Die Datenbanken in einer Verfügbarkeitsgruppe müssen Multiuser Datenbanken sein Sie dürfen nicht das AUTO_CLOSE Feature verwenden Sie müssen das Full Recovery Modell nutzen und es muss ein vollständiges Backup vorhanden sein Eine gegebene Datenbank kann sich nur in einer einzigen Verfügbarkeitsgruppe befinden und diese Datenbank düerfen nicht für Database Mirroring konfiguriert sein Microsoft empfiehl außerdem, dass der Verzeichnispfad einer Datenbank auf dem primären und sekundären Server identisch sein sollte Wie man sieht, eignen sich Verfügbarkeitsgruppen nicht, um HA und DR vollständig abzubilden. Die Unterscheidung zwischen der Instanzen-Ebene (FCI) und Datenbank-Ebene (Availability Groups) ist von hoher Bedeutung. Vor kurzem wurde mir gesagt, dass man mit den Verfügbarkeitsgruppen auf Shared Storage verzichten könne und dadurch Kosten spart. So weit so gut ... Man kann natürlich eine Installation rein mit Verfügbarkeitsgruppen und ohne FCI durchführen - aber man sollte sich dann darüber bewusst sein, was man dadurch alles nicht abgesichert hat - und dies wiederum für Desaster Recovery (DR) und SLAs (Service Level Agreements) bedeutet. Kurzum, um die Kombination aus beiden AlwaysOn Produkten und der damit verbundene Komplexität kommt man wohl in der Praxis nicht herum.    Availability Groups und WSFC AlwaysOn hängt von Windows Server Failover Clustering (WSFC) ab, um die aktuellen Rollen der Verfügbarkeitsreplikate einer Verfügbarkeitsgruppe zu überwachen und zu verwalten, und darüber zu entscheiden, wie ein Failover-Ereignis die Verfügbarkeitsreplikate betrifft. Das folgende Diagramm zeigt de Beziehung zwischen Verfügbarkeitsgruppen und WSFC:   Der Verfügbarkeitsmodus ist eine Eigenschaft jedes Verfügbarkeitsreplikats. Synychron und Asynchron können also gemischt werden: Availability Modus (Verfügbarkeitsmodus) Asynchroner Commit-Modus Primäres replikat schließt Transaktionen ohne Warten auf Sekundäres Synchroner Commit-Modus Primäres Replikat wartet auf Commit von sekundärem Replikat Failover Typen Automatic Manual Forced (mit möglichem Datenverlust) Synchroner Commit-Modus Geplanter, manueller Failover ohne Datenverlust Automatischer Failover ohne Datenverlust Asynchroner Commit-Modus Nur Forced, manueller Failover mit möglichem Datenverlust   Der SQL Server kennt keinen separaten Switchover Begriff wie in Oracle Data Guard. Für SQL Server werden alle Role Transitions als Failover bezeichnet. Tatsächlich unterstützt der SQL Server keinen Switchover für asynchrone Verbindungen. Es gibt nur die Form des Forced Failover mit möglichem Datenverlust. Eine ähnliche Fähigkeit wie der Switchover unter Oracle Data Guard ist so nicht gegeben.   SQL Sever FCI mit Availability Groups (Verfügbarkeitsgruppen) Neben den Verfügbarkeitsgruppen kann eine zweite Failover-Ebene eingerichtet werden, indem SQL Server FCI (auf Shared Storage) mit WSFC implementiert wird. Ein Verfügbarkeitesreplikat kann dann auf einer Standalone Instanz gehostet werden, oder einer FCI Instanz. Zum Verständnis: Die Verfügbarkeitsgruppen selbst benötigen kein Shared Storage. Diese Kombination kann verwendet werden für lokale HA auf Ebene der Instanz und DR auf Datenbank-Ebene durch Verfügbarkeitsgruppen. Das folgende Diagramm zeigt dieses Szenario:   Achtung! Hier handelt es sich nicht um ein Pendant zu Oracle RAC plus Data Guard, auch wenn das Bild diesen Eindruck vielleicht vermitteln mag - denn alle sekundären Knoten im FCI sind rein passiv. Es existiert außerdem eine weitere und ernsthafte Einschränkung: SQL Server Failover Cluster Instanzen (FCI) unterstützen nicht das automatische AlwaysOn Failover für Verfügbarkeitsgruppen. Jedes unter FCI gehostete Verfügbarkeitsreplikat kann nur für manuelles Failover konfiguriert werden.   Lesbare Sekundäre Replikate Ein oder mehrere Verfügbarkeitsreplikate in einer Verfügbarkeitsgruppe können für den lesenden Zugriff konfiguriert werden, wenn sie als sekundäres Replikat laufen. Dies ähnelt Oracle Active Data Guard, jedoch gibt es Einschränkungen. Alle Abfragen gegen die sekundäre Datenbank werden automatisch auf das Snapshot Isolation Level abgebildet. Es handelt sich dabei um eine Versionierung der Rows. Microsoft versuchte hiermit die Oracle MVRC (Multi Version Read Consistency) nachzustellen. Tatsächlich muss man die SQL Server Snapshot Isolation eher mit Oracle Flashback vergleichen. Bei der Implementierung des Snapshot Isolation Levels handelt sich um ein nachträglich aufgesetztes Feature und nicht um einen inhärenten Teil des Datenbank-Kernels, wie im Falle Oracle. (Ich werde hierzu in Kürze einen weiteren Blogbeitrag verfassen, wenn ich mich mit der neuen SQL Server 2012 Core Lizenzierung beschäftige.) Für die Praxis entstehen aus der Abbildung auf das Snapshot Isolation Level ernsthafte Restriktionen, derer man sich für den Betrieb in der Praxis bereits vorab bewusst sein sollte: Sollte auf der primären Datenbank eine aktive Transaktion zu dem Zeitpunkt existieren, wenn ein lesbares sekundäres Replikat in die Verfügbarkeitsgruppe aufgenommen wird, werden die Row-Versionen auf der korrespondierenden sekundären Datenbank nicht sofort vollständig verfügbar sein. Eine aktive Transaktion auf dem primären Replikat muss zuerst abgeschlossen (Commit oder Rollback) und dieser Transaktions-Record auf dem sekundären Replikat verarbeitet werden. Bis dahin ist das Isolation Level Mapping auf der sekundären Datenbank unvollständig und Abfragen sind temporär geblockt. Microsoft sagt dazu: "This is needed to guarantee that row versions are available on the secondary replica before executing the query under snapshot isolation as all isolation levels are implicitly mapped to snapshot isolation." (SQL Storage Engine Blog: AlwaysOn: I just enabled Readable Secondary but my query is blocked?)  Grundlegend bedeutet dies, dass ein aktives lesbares Replikat nicht in die Verfügbarkeitsgruppe aufgenommen werden kann, ohne das primäre Replikat vorübergehend stillzulegen. Da Leseoperationen auf das Snapshot Isolation Transaction Level abgebildet werden, kann die Bereinigung von Ghost Records auf dem primären Replikat durch Transaktionen auf einem oder mehreren sekundären Replikaten geblockt werden - z.B. durch eine lang laufende Abfrage auf dem sekundären Replikat. Diese Bereinigung wird auch blockiert, wenn die Verbindung zum sekundären Replikat abbricht oder der Datenaustausch unterbrochen wird. Auch die Log Truncation wird in diesem Zustant verhindert. Wenn dieser Zustand längere Zeit anhält, empfiehlt Microsoft das sekundäre Replikat aus der Verfügbarkeitsgruppe herauszunehmen - was ein ernsthaftes Downtime-Problem darstellt. Die Read-Only Workload auf den sekundären Replikaten kann eingehende DDL Änderungen blockieren. Obwohl die Leseoperationen aufgrund der Row-Versionierung keine Shared Locks halten, führen diese Operatioen zu Sch-S Locks (Schemastabilitätssperren). DDL-Änderungen durch Redo-Operationen können dadurch blockiert werden. Falls DDL aufgrund konkurrierender Lese-Workload blockiert wird und der Schwellenwert für 'Recovery Interval' (eine SQL Server Konfigurationsoption) überschritten wird, generiert der SQL Server das Ereignis sqlserver.lock_redo_blocked, welches Microsoft zum Kill der blockierenden Leser empfiehlt. Auf die Verfügbarkeit der Anwendung wird hierbei keinerlei Rücksicht genommen.   Keine dieser Einschränkungen existiert mit Oracle Active Data Guard.   Backups auf sekundären Replikaten  Über die sekundären Replikate können Backups (BACKUP DATABASE via Transact-SQL) nur als copy-only Backups einer vollständigen Datenbank, Dateien und Dateigruppen erstellt werden. Das Erstellen inkrementeller Backups ist nicht unterstützt, was ein ernsthafter Rückstand ist gegenüber der Backup-Unterstützung physikalischer Standbys unter Oracle Data Guard. Hinweis: Ein möglicher Workaround via Snapshots, bleibt ein Workaround. Eine weitere Einschränkung dieses Features gegenüber Oracle Data Guard besteht darin, dass das Backup eines sekundären Replikats nicht ausgeführt werden kann, wenn es nicht mit dem primären Replikat kommunizieren kann. Darüber hinaus muss das sekundäre Replikat synchronisiert sein oder sich in der Synchronisation befinden, um das Beackup auf dem sekundären Replikat erstellen zu können.   Vergleich von Microsoft AlwaysOn mit der Oracle MAA Ich komme wieder zurück auf die Eingangs erwähnte, mehrfach an mich gestellte Frage "Wann denn - und ob überhaupt - Oracle etwas Vergleichbares wie AlwaysOn bieten würde?" und meine damit verbundene (kurze) Irritation. Wenn Sie diesen Blogbeitrag bis hierher gelesen haben, dann kennen Sie jetzt meine darauf gegebene Antwort. Der eine oder andere Punkt traf dabei nicht immer auf Jeden zu, was auch nicht der tiefere Sinn und Zweck meiner Antwort war. Wenn beispielsweise kein Multi-Subnet mit im Spiel ist, sind alle diesbezüglichen Kritikpunkte zunächst obsolet. Was aber nicht bedeutet, dass sie nicht bereits morgen schon wieder zum Thema werden könnten (Sag niemals "Nie"). In manch anderes Fettnäpfchen tritt man wiederum nicht unbedingt in einer Testumgebung, sondern erst im laufenden Betrieb. Erst recht nicht dann, wenn man sich potenzieller Probleme nicht bewusst ist und keine dedizierten Tests startet. Und wer AlwaysOn erfolgreich positionieren möchte, wird auch gar kein Interesse daran haben, auf mögliche Schwachstellen und den besagten Teufel im Detail aufmerksam zu machen. Das ist keine Unterstellung - es ist nur menschlich. Außerdem ist es verständlich, dass man sich in erster Linie darauf konzentriert "was geht" und "was gut läuft", anstelle auf das "was zu Problemen führen kann" oder "nicht funktioniert". Wer will schon der Miesepeter sein? Für mich selbst gesprochen, kann ich nur sagen, dass ich lieber vorab von allen möglichen Einschränkungen wissen möchte, anstelle sie dann nach einer kurzen Zeit der heilen Welt schmerzhaft am eigenen Leib erfahren zu müssen. Ich bin davon überzeugt, dass es Ihnen nicht anders geht. Nachfolgend deshalb eine Zusammenfassung all jener Punkte, die ich im Vergleich zur Oracle MAA (Maximum Availability Architecture) als unbedingt Erwähnenswert betrachte, falls man eine Evaluierung von Microsoft AlwaysOn in Betracht zieht. 1. AlwaysOn ist eine komplexe Technologie Der SQL Server AlwaysOn Stack ist zusammengesetzt aus drei verschiedenen Technlogien: Windows Server Failover Clustering (WSFC) SQL Server Failover Cluster Instances (FCI) SQL Server Availability Groups (Verfügbarkeitsgruppen) Man kann eine derartige Lösung nicht als nahtlos bezeichnen, wofür auch die vielen von Microsoft dargestellten Einschränkungen sprechen. Während sich frühere SQL Server Versionen in Richtung eigener HA/DR Technologien entwickelten (wie Database Mirroring), empfiehlt Microsoft nun die Migration. Doch weshalb dieser Schwenk? Er führt nicht zu einem konsisten und robusten Angebot an HA/DR Technologie für geschäftskritische Umgebungen.  Liegt die Antwort in meiner These begründet, nach der "Windows was the God ..." noch immer gilt und man die Nachteile der allzu engen Kopplung mit Windows nicht sehen möchte? Entscheiden Sie selbst ... 2. Failover Cluster Instanzen - Kein RAC-Pendant Die SQL Server und Windows Server Clustering Technologie basiert noch immer auf dem veralteten Aktiv-Passiv Modell und führt zu einer Verschwendung von Systemressourcen. In einer Betrachtung von lediglich zwei Knoten erschließt sich auf Anhieb noch nicht der volle Mehrwert eines Aktiv-Aktiv Clusters (wie den Real Application Clusters), wie er von Oracle bereits vor zehn Jahren entwickelt wurde. Doch kennt man die Vorzüge der Skalierbarkeit durch einfaches Hinzufügen weiterer Cluster-Knoten, die dann alle gemeinsam als ein einziges logisches System zusammenarbeiten, versteht man was hinter dem Motto "Pay-as-you-Grow" steckt. In einem Aktiv-Aktiv Cluster geht es zwar auch um Hochverfügbarkeit - und ein Failover erfolgt zudem schneller, als in einem Aktiv-Passiv Modell - aber es geht eben nicht nur darum. An dieser Stelle sei darauf hingewiesen, dass die Oracle 11g Standard Edition bereits die Nutzung von Oracle RAC bis zu vier Sockets kostenfrei beinhaltet. Möchten Sie dazu Windows nutzen, benötigen Sie keine Windows Server Enterprise Edition, da Oracle 11g die eigene Clusterware liefert. Sie kommen in den Genuss von Hochverfügbarkeit und Skalierbarkeit und können dazu die günstigere Windows Server Standard Edition nutzen. 3. SQL Server Multi-Subnet Clustering - Abhängigkeit zu 3rd Party Storage Mirroring  Die SQL Server Multi-Subnet Clustering Architektur unterstützt den Aufbau eines Stretch Clusters, basiert dabei aber auf dem Aktiv-Passiv Modell. Das eigentlich Problematische ist jedoch, dass man sich zur Absicherung der Datenbank auf 3rd Party Storage Mirroring Technologie verlässt, ohne Integration zwischen dem Windows Server Failover Clustering (WSFC) und der darunterliegenden Mirroring Technologie. Wenn nun im Cluster ein Failover auf Instanzen-Ebene erfolgt, existiert keine Koordination mit einem möglichen Failover auf Ebene des Storage-Array. 4. Availability Groups (Verfügbarkeitsgruppen) - Vier, oder doch nur Zwei? Ein primäres Replikat erlaubt bis zu vier sekundäre Replikate innerhalb einer Verfügbarkeitsgruppe, jedoch nur zwei im Synchronen Commit Modus. Während dies zwar einen Vorteil gegenüber dem stringenten 1:1 Modell unter Database Mirroring darstellt, fällt der SQL Server 2012 damit immer noch weiter zurück hinter Oracle Data Guard mit bis zu 30 direkten Stanbdy Zielen - und vielen weiteren durch kaskadierende Ziele möglichen. Damit eignet sich Oracle Active Data Guard auch für die Bereitstellung einer Reader-Farm Skalierbarkeit für Internet-basierende Unternehmen. Mit AwaysOn Verfügbarkeitsgruppen ist dies nicht möglich. 5. Availability Groups (Verfügbarkeitsgruppen) - kein asynchrones Switchover  Die Technologie der Verfügbarkeitsgruppen wird auch als geeignetes Mittel für administrative Aufgaben positioniert - wie Upgrades oder Wartungsarbeiten. Man muss sich jedoch einem gravierendem Defizit bewusst sein: Im asynchronen Verfügbarkeitsmodus besteht die einzige Möglichkeit für Role Transition im Forced Failover mit Datenverlust! Um den Verlust von Daten durch geplante Wartungsarbeiten zu vermeiden, muss man den synchronen Verfügbarkeitsmodus konfigurieren, was jedoch ernstzunehmende Auswirkungen auf WAN Deployments nach sich zieht. Spinnt man diesen Gedanken zu Ende, kommt man zu dem Schluss, dass die Technologie der Verfügbarkeitsgruppen für geplante Wartungsarbeiten in einem derartigen Umfeld nicht effektiv genutzt werden kann. 6. Automatisches Failover - Nicht immer möglich Sowohl die SQL Server FCI, als auch Verfügbarkeitsgruppen unterstützen automatisches Failover. Möchte man diese jedoch kombinieren, wird das Ergebnis kein automatisches Failover sein. Denn ihr Zusammentreffen im Failover-Fall führt zu Race Conditions (Wettlaufsituationen), weshalb diese Konfiguration nicht länger das automatische Failover zu einem Replikat in einer Verfügbarkeitsgruppe erlaubt. Auch hier bestätigt sich wieder die tiefere Problematik von AlwaysOn, mit einer Zusammensetzung aus unterschiedlichen Technologien und der Abhängigkeit zu Windows. 7. Problematische RTO (Recovery Time Objective) Microsoft postioniert die SQL Server Multi-Subnet Clustering Architektur als brauchbare HA/DR Architektur. Bedenkt man jedoch die Problematik im Zusammenhang mit DNS Replikation und den möglichen langen Wartezeiten auf Client-Seite von bis zu 16 Minuten, sind strenge RTO Anforderungen (Recovery Time Objectives) nicht erfüllbar. Im Gegensatz zu Oracle besitzt der SQL Server keine Datenbank-integrierten Technologien, wie Oracle Fast Application Notification (FAN) oder Oracle Fast Connection Failover (FCF). 8. Problematische RPO (Recovery Point Objective) SQL Server ermöglicht Forced Failover (erzwungenes Failover), bietet jedoch keine Möglichkeit zur automatischen Übertragung der letzten Datenbits von einem alten zu einem neuen primären Replikat, wenn der Verfügbarkeitsmodus asynchron war. Oracle Data Guard hingegen bietet diese Unterstützung durch das Flush Redo Feature. Dies sichert "Zero Data Loss" und beste RPO auch in erzwungenen Failover-Situationen. 9. Lesbare Sekundäre Replikate mit Einschränkungen Aufgrund des Snapshot Isolation Transaction Level für lesbare sekundäre Replikate, besitzen diese Einschränkungen mit Auswirkung auf die primäre Datenbank. Die Bereinigung von Ghost Records auf der primären Datenbank, wird beeinflusst von lang laufenden Abfragen auf der lesabaren sekundären Datenbank. Die lesbare sekundäre Datenbank kann nicht in die Verfügbarkeitsgruppe aufgenommen werden, wenn es aktive Transaktionen auf der primären Datenbank gibt. Zusätzlich können DLL Änderungen auf der primären Datenbank durch Abfragen auf der sekundären blockiert werden. Und imkrementelle Backups werden hier nicht unterstützt.   Keine dieser Restriktionen existiert unter Oracle Data Guard.

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  • What free space thresholds/limits are advisable for 640 GB and 2 TB hard disk drives with ZEVO ZFS on OS X?

    - by Graham Perrin
    Assuming that free space advice for ZEVO will not differ from advice for other modern implementations of ZFS … Question Please, what percentages or amounts of free space are advisable for hard disk drives of the following sizes? 640 GB 2 TB Thoughts A standard answer for modern implementations of ZFS might be "no more than 96 percent full". However if apply that to (say) a single-disk 640 GB dataset where some of the files most commonly used (by VirtualBox) are larger than 15 GB each, then I guess that blocks for those files will become sub optimally spread across the platters with around 26 GB free. I read that in most cases, fragmentation and defragmentation should not be a concern with ZFS. Sill, I like the mental picture of most fragments of a large .vdi in reasonably close proximity to each other. (Do features of ZFS make that wish for proximity too old-fashioned?) Side note: there might arise the question of how to optimise performance after a threshold is 'broken'. If it arises, I'll keep it separate. Background On a 640 GB StoreJet Transcend (product ID 0x2329) in the past I probably went beyond an advisable threshold. Currently the largest file is around 17 GB –  – and I doubt that any .vdi or other file on this disk will grow beyond 40 GB. (Ignore the purple masses, those are bundles of 8 MB band files.) Without HFS Plus: the thresholds of twenty, ten and five percent that I associate with Mobile Time Machine file system need not apply. I currently use ZEVO Community Edition 1.1.1 with Mountain Lion, OS X 10.8.2, but I'd like answers to be not too version-specific. References, chronological order ZFS Block Allocation (Jeff Bonwick's Blog) (2006-11-04) Space Maps (Jeff Bonwick's Blog) (2007-09-13) Doubling Exchange Performance (Bizarre ! Vous avez dit Bizarre ?) (2010-03-11) … So to solve this problem, what went in 2010/Q1 software release is multifold. The most important thing is: we increased the threshold at which we switched from 'first fit' (go fast) to 'best fit' (pack tight) from 70% full to 96% full. With TB drives, each slab is at least 5GB and 4% is still 200MB plenty of space and no need to do anything radical before that. This gave us the biggest bang. Second, instead of trying to reuse the same primary slabs until it failed an allocation we decided to stop giving the primary slab this preferential threatment as soon as the biggest allocation that could be satisfied by a slab was down to 128K (metaslab_df_alloc_threshold). At that point we were ready to switch to another slab that had more free space. We also decided to reduce the SMO bonus. Before, a slab that was 50% empty was preferred over slabs that had never been used. In order to foster more write aggregation, we reduced the threshold to 33% empty. This means that a random write workload now spread to more slabs where each one will have larger amount of free space leading to more write aggregation. Finally we also saw that slab loading was contributing to lower performance and implemented a slab prefetch mechanism to reduce down time associated with that operation. The conjunction of all these changes lead to 50% improved OLTP and 70% reduced variability from run to run … OLTP Improvements in Sun Storage 7000 2010.Q1 (Performance Profiles) (2010-03-11) Alasdair on Everything » ZFS runs really slowly when free disk usage goes above 80% (2010-07-18) where commentary includes: … OpenSolaris has changed this in onnv revision 11146 … [CFT] Improved ZFS metaslab code (faster write speed) (2010-08-22)

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  • Why is this mod_rewrite RewriteRule directive not working in the .htaccess file?

    - by morgant
    I've got a site that was hosted on a linux el cheapo hosting service that I'm migrating to my Mac OS X 10.5 Leopard Server server running Apache 2.2.8 & PHP 5.2.5 w/rewrite_module enabled and AllowOverride All, but I'm running into an issue with the following lines in the .htaccess file: RewriteEngine On #RewriteRule ^view/([^/\.]+)/?$ /view.php?item=$1 [L] #RewriteRule ^order/([^/\.]+)/?$ /order.php?item=$1 [L] RewriteRule ^category/([^/\.]+)/?$ /category.php?category=$1 [L] As you can see, I've commented out the RewriteRule directives for /view/ and /order/, so I'm only dealing with /category/. When I attempt to load http://domain.tld/category/2/ it runs category.php (I've added debug code to confirm), but $_SERVER['REQUEST_URI'] comes through as /category/2/ and $_GET['category'] comes through as empty. I'm usually fine with troubleshooting .htaccess files and mod_rewrite directives, but this one's got me stumped for some reason. Update: I followed Josh's suggestion and here's the what's dumped to mod_rewrite.log when I try to access http://domain.tld/category/2/: 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (2) init rewrite engine with requested uri /category/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) applying pattern '.*' to uri '/category/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (1) pass through /category/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] add path info postfix: /Library/WebServer/Documents/tld.domain.www/category.php -> /Library/WebServer/Documents/tld.domain.www/category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] strip per-dir prefix: /Library/WebServer/Documents/tld.domain.www/category.php/13 -> category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] applying pattern '^category/([^/\.]+)/?$' to uri 'category.php/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (1) [perdir /Library/WebServer/Documents/tld.domain.www/] pass through /Library/WebServer/Documents/tld.domain.www/category.php 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] add path info postfix: /Library/WebServer/Documents/tld.domain.www/category.php -> /Library/WebServer/Documents/tld.domain.www/category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] strip per-dir prefix: /Library/WebServer/Documents/tld.domain.www/category.php/13 -> category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] applying pattern '^category/([^/\.]+)/?$' to uri 'category.php/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (1) [perdir /Library/WebServer/Documents/tld.domain.www/] pass through /Library/WebServer/Documents/tld.domain.www/category.php 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (2) init rewrite engine with requested uri /13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (3) applying pattern '.*' to uri '/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (1) pass through /13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] strip per-dir prefix: /Library/WebServer/Documents/tld.domain.www/13 -> 13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] applying pattern '^category/([^/\.]+)/?$' to uri '13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (1) [perdir /Library/WebServer/Documents/tld.domain.www/] pass through /Library/WebServer/Documents/tld.domain.www/13

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  • Windows: what is the difference between DEP always on and DEP opt-out with no exceptions?

    - by Peter Mortensen
    What is the difference between DEP always on ("/NoExecute=AlwaysOn" in boot.ini) and DEP opt-out ( "/NoExecute=OptOut" in boot.ini) with no exceptions? "no exceptions" = empty list of programs for which DEP does not apply. DEP = Data Execution Prevention (hardware). One would expect it to work the same way, but it makes a difference for some applications. E.g. for all versions of UltraEdit 14 (14.2). It crashes at startup for DEP always on, at least on Microsoft Windows XP Professional Edition x64 edition. (2010-03-11: this problem has been fixed with UltraEdit 15.2 and later.) Update 1: I think this difference is caused by the backdoors that Microsoft has put into hardware DEP for OptOut, according to Fabrice Roux (see below). In the case of IrfanView, for which Steve Gibson observed the same difference as I did for UltraEdit (see below), the difference is caused by a non-DEP aware EXE packer (ASPack) that Microsoft coded a backdoor for. Is there a difference between Windows XP, Windows Vista and Windows 7 ? Is there a difference between 32 bit and 64 bit versions of Windows ? Sources: From [http://blog.fabriceroux.com/index.php/2007/02/26/hardware_dep_has_a_backdoor?blog=1], "Hardware DEP has a backdoor" by Fabrice Roux. 2007-02-26. "IrfanView was not using any trick to evade DEP ... Microsoft just coded a backdoor used only in OPTOUT. Bascially Microsoft checks the executable header for a section matching one of the 3 strings. If one these strings is found, DEP will be turned OFF for this application by windows. ... 'aspack', 'pcle', 'sforce'" From [http://www.grc.com/sn/sn-078.htm], by Steve Gibson. "I can’t find any documentation on Microsoft’s site anywhere, because we’re seeing a difference between always-on and opt-out. That is, you would imagine that always-on mode would be the same as opting out if you weren’t having any opt-out programs. It turns out it’s not the case. For example ... the IrfanView file viewer ... runs fine in opt-out mode, even if it has not been opted out. But it won’t launch, Windows blocks it from launching ... in always-on mode." From [http://www.grc.com/sn/sn-083.htm], by Steve Gibson. "... IrfanView ... won’t run with DEP turned on. It’s because it uses an EXE packer, an executable compression program called ASPack. And it makes sense that it wouldn’t because naturally an executable compressor has got to decompress the executable, so it allocates a bunch of data memory into which it decompresses the compressed executable, and then it runs it. Well, it’s running a data allocation, which is exactly what DEP is designed to stop. On the other hand, UPX, which is actually the leading and most popular EXE compressor, it’s DEP- compatible because those guys realized, hey, when we allocate this memory, we should mark the pages as executable."

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  • stunnel crashing

    - by Jay
    I'm trying to use stunnel to secure a legacy application's communications. I can't seem to get it setup and working. Can anyone provide any hints where I'm going wrong? Here's what I'm trying to accomplish: A windows service on a client machine connects to a server on port 7000 using TCP. I'd like to encrypt the communication between client and server. Here's what I've tried: Created a new server that accepts ssl connections on port 7443. Got a certificate for the server and installed it. That seems to work with my test setup. Installed stunnel on my windows machine (version 7.43 from the distribution archive file). Installed libssl32.dll and libeay32.dll in the same directory as stunnel.exe ( from the openssl-0.9.8h-1 binary distribution). Installed it as a service using "stunnel -install" Configured stunnel as follows: debug=7 output=C:\p4\internal\Utility\Proxy\proxy.log service=Proxy taskbar=no [exchange] accept=7000 client=yes connect=proxy.blah.com:7443 I changed my hosts file to trick the old application into connecting through stunnel: server.blah.com 127.0.0.1 # when client looks up server it goes to stunnel proxy.blah.com IP-address-of-server.blah.com # stunnel connects to new server "server.blah.com" now resolves to the machine it's running on (i.e. stunnel). "proxy.blah.com" goes to the real server. stunnel should connect to the server. I start the stunnel service and try to connect. It looks like it's working but the stunnel service just shuts down with no message. 2010.04.19 13:16:21 LOG5[4924:3716]: stunnel 4.33 on x86-pc-mingw32-gnu with OpenSSL 0.9.8h 28 May 2008 2010.04.19 13:16:21 LOG5[4924:3716]: Threading:WIN32 SSL:ENGINE Sockets:SELECT,IPv6 2010.04.19 13:16:49 LOG5[4924:3748]: Service exchange accepted connection from 127.0.0.1:4134 2010.04.19 13:16:49 LOG6[4924:3748]: connect_blocking: connecting x.80.60.32:7443 2010.04.19 13:16:49 LOG5[4924:3748]: connect_blocking: connected x.80.60.32:7443 2010.04.19 13:16:49 LOG5[4924:3748]: Service exchange connected remote server from x.253.120.19:4135 2010.04.19 13:20:24 LOG5[3668:3856]: Reading configuration from file stunnel.conf 2010.04.19 13:20:24 LOG7[3668:3856]: Snagged 64 random bytes from C:/.rnd 2010.04.19 13:20:24 LOG7[3668:3856]: Wrote 1024 new random bytes to C:/.rnd 2010.04.19 13:20:24 LOG7[3668:3856]: RAND_status claims sufficient entropy for the PRNG 2010.04.19 13:20:24 LOG7[3668:3856]: PRNG seeded successfully 2010.04.19 13:20:24 LOG7[3668:3856]: SSL context initialized for service exchange 2010.04.19 13:20:24 LOG5[3668:3856]: Configuration successful 2010.04.19 13:20:24 LOG5[3668:3856]: No limit detected for the number of clients 2010.04.19 13:20:24 LOG7[3668:3856]: FD=312 in non-blocking mode 2010.04.19 13:20:24 LOG7[3668:3856]: Option SO_REUSEADDR set on accept socket 2010.04.19 13:20:24 LOG7[3668:3856]: Service exchange bound to 0.0.0.0:7000 2010.04.19 13:20:24 LOG7[3668:3856]: Service exchange opened FD=312 2010.04.19 13:20:24 LOG5[3668:3856]: stunnel 4.33 on x86-pc-mingw32-gnu with OpenSSL 0.9.8h 28 May 2008 2010.04.19 13:20:24 LOG5[3668:3856]: Threading:WIN32 SSL:ENGINE Sockets:SELECT,IPv6 2010.04.19 13:21:02 LOG7[3668:4556]: Service exchange accepted FD=372 from 127.0.0.1:4156 2010.04.19 13:21:02 LOG7[3668:4556]: Creating a new thread 2010.04.19 13:21:02 LOG7[3668:4556]: New thread created 2010.04.19 13:21:02 LOG7[3668:3756]: Service exchange started 2010.04.19 13:21:02 LOG7[3668:3756]: FD=372 in non-blocking mode 2010.04.19 13:21:02 LOG5[3668:3756]: Service exchange accepted connection from 127.0.0.1:4156 2010.04.19 13:21:02 LOG7[3668:3756]: FD=396 in non-blocking mode 2010.04.19 13:21:02 LOG6[3668:3756]: connect_blocking: connecting x.80.60.32:7443 2010.04.19 13:21:02 LOG7[3668:3756]: connect_blocking: s_poll_wait x.80.60.32:7443: waiting 10 seconds 2010.04.19 13:21:02 LOG5[3668:3756]: connect_blocking: connected x.80.60.32:7443 2010.04.19 13:21:02 LOG5[3668:3756]: Service exchange connected remote server from x.253.120.19:4157 2010.04.19 13:21:02 LOG7[3668:3756]: Remote FD=396 initialized 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): before/connect initialization 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write client hello A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read server hello A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read server certificate A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read server done A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write client key exchange A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write change cipher spec A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write finished A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 flush data 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read finished A The client thinks the connection is closed: No connection could be made because the target machine actively refused it 127.0.0.1:7000 at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.Sockets.Socket.Connect(EndPoint remoteEP) at Service.ConnUtility.Connect() Any suggestions?

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  • How do I troubleshoot a "Bad Request" in Apache2?

    - by Nick
    I have a PHP application that loads for all URLs except the home page. Visiting "https://my.site.com/" produces a "Bad Request" error message. Any other URL, for example, "https://my.site.com/SomePage/" works just fine. It's only the home page that does not work. All pages use mod_rewrite and get routed through a single dispatch script, Director.php. Accessing Director.php directly also produces the "Bad Request" error. BUT- ALL of the other requests go through Director, and they all work just fine, (excluding the home page), so it can't be an issue with the Director.php script? OR can it? I'm not seeing anything in the Apache2 error log, and I'm not seeing any PHP errors in the PHP Error log. I've tried changing the first line of Director.php to read: echo 'test'; exit(); But I still get a "Bad Request". This is the rewrite log for a request to the home page: 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da48b28/initial] (2) init rewrite engine with requested uri / 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da48b28/initial] (3) applying pattern '^/([a-zA-Z0-9\-\_]+)/$' to uri '/' 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da48b28/initial] (3) applying pattern '^/([a-zA-Z0-9\-\_]+)/([a-zA-Z0-9\-\_]+)/$' to uri '/' 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da48b28/initial] (1) pass through / 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da5a298/subreq] (2) init rewrite engine with requested uri /Director.php 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da5a298/subreq] (2) rewrite '/Director.php' - '-[L,NC]' 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da5a298/subreq] (3) applying pattern '^/([a-zA-Z0-9\-\_]+)/$' to uri '-[L,NC]' 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da5a298/subreq] (3) applying pattern '^/([a-zA-Z0-9\-\_]+)/([a-zA-Z0-9\-\_]+)/$' to uri '-[L,NC]' 123.123.123.123 - - [18/Feb/2011:05:38:49 +0000] [my.site.com/sid#7f273d77cb80][rid#7f273da5a298/subreq] (2) local path result: -[L,NC] Apache2 Access Log my.site.com:443 123.123.123.123 - - [18/Feb/2011:05:44:19 +0000] "GET / HTTP/1.1" 400 3223 "-" "Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.8) Gecko/20100723 Ubuntu/10.04 (lucid) Firefox/3.6.8" Any ideas? I don't know what else to try? UPDATE: Here's my vhost conf: RewriteEngine On RewriteLog "/LiveWebs/mysite.com/rewrite.log" RewriteLogLevel 5 # Dont rewite Crons folder ReWriteRule ^/Crons/ - [L,NC] ReWriteRule ^/phpmyadmin - [L,NC] ReWriteRule .php$ -[L,NC] # this is the problem!! RewriteCond %{REQUEST_URI} !^/images/ [NC] RewriteRule ^/([a-zA-Z0-9\-\_]+)/$ /Director.php?rt=$1 [L,QSA] RewriteCond %{REQUEST_URI} !^/images/ [NC] RewriteRule ^/([a-zA-Z0-9\-\_]+)/([a-zA-Z0-9\-\_]+)/$ /Director.php?rt=$1&action=$2 [L,QSA] The problem is the line "ReWriteRule .php$ -[L,NC]". When I comment it out, the home page loads. The question is, how do I make URLS that actually end in .php go straight through (without breaking the home page)?

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  • Why is this mod_rewrite RewriteRule directive not working in the .htaccess file?

    - by morgant
    I've got a site that was hosted on a linux el cheapo hosting service that I'm migrating to my Mac OS X 10.5 Leopard Server server running Apache 2.2.8 & PHP 5.2.5 w/rewrite_module enabled and AllowOverride All, but I'm running into an issue with the following lines in the .htaccess file: RewriteEngine On #RewriteRule ^view/([^/\.]+)/?$ /view.php?item=$1 [L] #RewriteRule ^order/([^/\.]+)/?$ /order.php?item=$1 [L] RewriteRule ^category/([^/\.]+)/?$ /category.php?category=$1 [L] As you can see, I've commented out the RewriteRule directives for /view/ and /order/, so I'm only dealing with /category/. When I attempt to load http://domain.tld/category/2/ it runs category.php (I've added debug code to confirm), but $_SERVER['REQUEST_URI'] comes through as /category/2/ and $_GET['category'] comes through as empty. I'm usually fine with troubleshooting .htaccess files and mod_rewrite directives, but this one's got me stumped for some reason. Update: I followed Josh's suggestion and here's the what's dumped to mod_rewrite.log when I try to access http://domain.tld/category/2/: 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (2) init rewrite engine with requested uri /category/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) applying pattern '.*' to uri '/category/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (1) pass through /category/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] add path info postfix: /Library/WebServer/Documents/tld.domain.www/category.php -> /Library/WebServer/Documents/tld.domain.www/category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] strip per-dir prefix: /Library/WebServer/Documents/tld.domain.www/category.php/13 -> category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] applying pattern '^category/([^/\.]+)/?$' to uri 'category.php/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6aa98/subreq] (1) [perdir /Library/WebServer/Documents/tld.domain.www/] pass through /Library/WebServer/Documents/tld.domain.www/category.php 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] add path info postfix: /Library/WebServer/Documents/tld.domain.www/category.php -> /Library/WebServer/Documents/tld.domain.www/category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] strip per-dir prefix: /Library/WebServer/Documents/tld.domain.www/category.php/13 -> category.php/13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] applying pattern '^category/([^/\.]+)/?$' to uri 'category.php/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b5ea98/initial] (1) [perdir /Library/WebServer/Documents/tld.domain.www/] pass through /Library/WebServer/Documents/tld.domain.www/category.php 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (2) init rewrite engine with requested uri /13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (3) applying pattern '.*' to uri '/13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (1) pass through /13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] strip per-dir prefix: /Library/WebServer/Documents/tld.domain.www/13 -> 13 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (3) [perdir /Library/WebServer/Documents/tld.domain.www/] applying pattern '^category/([^/\.]+)/?$' to uri '13' 65.19.81.253 - - [22/Oct/2009:17:31:53 --0400] [domain.tld/sid#100aae0b0][rid#100b6ea98/subreq] (1) [perdir /Library/WebServer/Documents/tld.domain.www/] pass through /Library/WebServer/Documents/tld.domain.www/13

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  • Extract tar with multiple tars inside?

    - by Andrew Fashion
    Is there a way to untar a file with multiple tars inside? It's suppose to just untar everything inside including untarring the tars inside the tar... With windows it does it, quite annoying I can't figure it out on linux... Here is what I am doing: # tar -xvf socialengine4.0.5p1.tar core-base-4.0.5.tar core-install-4.0.7.tar external-autocompleter-4.0.0.tar external-calendar-4.0.1.tar external-chootools-4.0.3.tar external-fancyupload-4.0.1.tar external-firebug-4.0.0.tar external-flowplayer-4.0.0.tar external-moocomet-4.0.0.tar external-moocrop-4.0.0.tar external-moolasso-4.0.0.tar external-mootools-4.0.2.tar external-mootree-4.0.0.tar external-open-flash-chart-4.0.0.tar external-smoothbox-4.0.0.tar external-swfobject-4.0.0.tar external-tagger-4.0.2.tar external-tinymce-4.0.2.tar library-engine-4.0.5.tar library-facebook-4.0.0.tar library-ofc-4.0.0.tar library-pear-4.0.1.tar library-scaffold-4.0.3.tar module-activity-4.0.5p1.tar module-announcement-4.0.3.tar module-authorization-4.0.5.tar module-core-4.0.5.tar module-fields-4.0.5p1.tar module-invite-4.0.3.tar module-messages-4.0.5.tar module-network-4.0.5p1.tar module-storage-4.0.4.tar module-user-4.0.5.tar widget-rss-4.0.2.tar widget-weather-4.0.0.tar changelog.html [root@D18634 se4]# ls -l total 36980 -rw-r--r-- 1 1000 1000 27188 Oct 8 15:39 changelog.html -rw-r--r-- 1 1000 1000 359424 Oct 8 16:13 core-base-4.0.5.tar -rw-r--r-- 1 1000 1000 1122304 Oct 8 16:13 core-install-4.0.7.tar -rw-r--r-- 1 1000 1000 38400 Oct 8 16:13 external-autocompleter-4.0.0.tar -rw-r--r-- 1 1000 1000 100352 Oct 8 16:13 external-calendar-4.0.1.tar -rw-r--r-- 1 1000 1000 31232 Oct 8 16:13 external-chootools-4.0.3.tar -rw-r--r-- 1 1000 1000 66560 Oct 8 16:13 external-fancyupload-4.0.1.tar -rw-r--r-- 1 1000 1000 85504 Oct 8 16:13 external-firebug-4.0.0.tar -rw-r--r-- 1 1000 1000 216576 Oct 8 16:13 external-flowplayer-4.0.0.tar -rw-r--r-- 1 1000 1000 11776 Oct 8 16:13 external-moocomet-4.0.0.tar -rw-r--r-- 1 1000 1000 16384 Oct 8 16:13 external-moocrop-4.0.0.tar -rw-r--r-- 1 1000 1000 27648 Oct 8 16:13 external-moolasso-4.0.0.tar -rw-r--r-- 1 1000 1000 1445376 Oct 8 16:13 external-mootools-4.0.2.tar -rw-r--r-- 1 1000 1000 45568 Oct 8 16:13 external-mootree-4.0.0.tar -rw-r--r-- 1 1000 1000 330240 Oct 8 16:13 external-open-flash-chart-4.0.0.tar -rw-r--r-- 1 1000 1000 43008 Oct 8 16:13 external-smoothbox-4.0.0.tar -rw-r--r-- 1 1000 1000 18432 Oct 8 16:13 external-swfobject-4.0.0.tar -rw-r--r-- 1 1000 1000 19968 Oct 8 16:13 external-tagger-4.0.2.tar -rw-r--r-- 1 1000 1000 5711360 Oct 8 16:13 external-tinymce-4.0.2.tar -rw-r--r-- 1 1000 1000 1230848 Oct 8 16:13 library-engine-4.0.5.tar -rw-r--r-- 1 1000 1000 28672 Oct 8 16:13 library-facebook-4.0.0.tar -rw-r--r-- 1 1000 1000 125952 Oct 8 16:13 library-ofc-4.0.0.tar -rw-r--r-- 1 1000 1000 1715200 Oct 8 16:13 library-pear-4.0.1.tar -rw-r--r-- 1 1000 1000 340480 Oct 8 16:13 library-scaffold-4.0.3.tar -rw-r--r-- 1 1000 1000 354304 Oct 8 16:13 module-activity-4.0.5p1.tar -rw-r--r-- 1 root root 327680 Jan 8 02:37 module-albums-4.0.5.tar -rw-r--r-- 1 1000 1000 80896 Oct 8 16:13 module-announcement-4.0.3.tar -rw-r--r-- 1 1000 1000 147456 Oct 8 16:13 module-authorization-4.0.5.tar -rw-r--r-- 1 1000 1000 2643968 Oct 8 16:13 module-core-4.0.5.tar -rw-r--r-- 1 root root 665600 Jan 8 02:37 module-events-4.0.5.tar -rw-r--r-- 1 1000 1000 377344 Oct 8 16:13 module-fields-4.0.5p1.tar -rw-r--r-- 1 root root 501760 Jan 8 02:37 module-forum-4.0.5p1.tar -rw-r--r-- 1 1000 1000 81408 Oct 8 16:14 module-invite-4.0.3.tar -rw-r--r-- 1 1000 1000 147968 Oct 8 16:14 module-messages-4.0.5.tar -rw-r--r-- 1 1000 1000 111616 Oct 8 16:14 module-network-4.0.5p1.tar -rw-r--r-- 1 1000 1000 99840 Oct 8 16:14 module-storage-4.0.4.tar -rw-r--r-- 1 1000 1000 844288 Oct 8 16:14 module-user-4.0.5.tar -rw-r--r-- 1 root root 18094080 Jan 8 02:40 socialengine4.0.5p1.tar -rw-r--r-- 1 1000 1000 12288 Oct 8 16:14 widget-rss-4.0.2.tar -rw-r--r-- 1 1000 1000 13824 Oct 8 16:14 widget-weather-4.0.0.tar

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  • Where should I go with hosting my site: VPS, GAE, another option?

    - by Jonathan Hayward
    My website, http://JonathansCorner.com/, began life before 1994 as www.imsa.edu/~jhayward/ and has been through various iterations and improvements to content, HTML, and the like, but remains a literature site that is from a web administrator's perspective fairly simple and primitive: a fair amount of static HTML and supporting files, a little bit of CGI and URI rewriting, .htaccess files providing Expires: headers and the like. An associated site demoes various CGI scripts that fall under the category of "and other creations"; the site as a whole has the purpose of sharing my creative works, and so far a fairly rudimentary use of Apache functionality, supported by Unix tools to, for instance, update RSS feed and the "starting point" link on the home page, has served that purpose fairly well. I looked around here on web hosting, and found the note on web host reccommendations as a good note for "What are some of people's favorite web hosts overall," but I wanted to ask a more focused question of "What are the best web hosts for criteria XYZ:" I am looking at a VPS so I will have root, be able to install stuff and edit Apache's config files etc., running Gentoo or other Linux, BSD, or the like. I would like a system that is secure enough that the host's vulnerabilities are mostly the ones that come along with what I am trying to do: that is, I won't be trying to administer and secure an ancient Linux like some have complained about at 1and1. I would like good uptime/reliability and competent support staff: if the level 1 help desk is going to tell me to go to "My Computer" on a Linux box, I'd like to be able to get past them. Ideally I would like a site hosted within some place that will have low latency for U.S. visitors in particular. I would like a hosting solution that will be with a stable business, one that will probably be around, and one unlikely to vanish without warning. With those things specified, I would be interested in knowing what are the less expensive options. (I expect that some of the things I've specified will knock out all of the cheapest options, but I'm still interested in price.) With all that stated, I'd like to back up a bit and look at whether I am asking the right question. I am concerned that the above is a very good way of asking, "How can I keep my site in line with the wave of the past?" I am wondering if it might be specifically wiser to look to adapt my site to newer technologies instead of trying to keep it on older technologies. For instance, while I would hardly portray my site as a way to show off the full power of Google App Engine, the main site at least should be a straightforward port if I were to do that. And beyond Google App Engine, my knowledge of cloud solutions is basic. If it is a better and more future-proof solution to port my site to another kind of solution, I would be interested in knowing where those future-proof solutions lie. So I would be interested in wisdom. If the question I asked in detail is still a good question to be asking, what would people suggest? Or if I should seriously consider porting my site to a newer basic option, what should I try there? Any thoughts would be appreciated.

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  • Wordpress Permissions OS X & MAMP

    - by Matt2020
    I have installed several local versions of Wordpress for development purposes. After the install I can create posts, pages and edit admin options. However as soon as try to upload images which would be saved in wp_content/uploads I get an error: Upload Error: Unable to create directory ...../blog/wp-content/uploads/2011/05. Is its parent directory writable by the server? Looks like MAMP server runs as user _www The blog directory is owned by User1 and the group User1 _www is not in the User1 group, should it be? I do not want to chmod 777 or 765 on the directories just to get it going. Googled up a couple of references: http://codex.wordpress.org/Changing_File_Permissions in "Permission Scheme for WordPress" All files should be owned by your user (ftp) account on your web server, and should be writable by that account. On shared hosts, files should never be owned by the webserver process itself (sometimes this is www, or apache, or nobody user). Any file that needs write access from WordPress should be owned or group-owned by the user account used by the WordPress (which may be different than the server account). For example, you may have a user account that lets you FTP files back and forth to your server, but your server itself may run using a separate user, in a separate usergroup, such as dhapache or nobody. If WordPress is running as the FTP account, that account needs to have write access, i.e., be the owner of the files, or belong to a group that has write access. In the latter case, that would mean permissions are set more permissively than default (for example, 775 rather than 755 for folders, and 664 instead of 644). User and group are User1 (which is admin). Running "ps aux | grep httpd" is running as _www So I think this means Wordpress is running as user _www. So the advice seems contradictory: "files should never be owned by the webserver process" i.e. _www but then later it says "Any file that needs write access from WordPress should be owned or group-owned by the user account used by the WordPress" So isn't this _www again? Another search found this url http://dancingengineer.com/computing/2009/07/how-to-install-wordpress-on-mac-os-x-leopard States Which says: My preferred way to do this is to change the group of the wordpress directory and its contents to _www and give write permissions to the group. Keep the owner as your "username". $ cd /Users/"username"/Sites $ sudo chown -R username:_www wordpress_directory $ sudo chmod -R g+w wordpress_directory However, when I tried this, it did not work for automatic upgrades to newer versions of WordPress although it worked for automatically updating the .htaccess file for pretty permalinks. It is not entirely clear to me what should be done. This last suggestion seems to be saying change the group from User1 to _www and give the group write access, but Wordpress upgrades won't work. Is this the right solution? I would have thought there would be a clear way to set this up on OS X 10.6? Be great if there was a plugin that could run a script for each of the main OS's that Wordpress runs on.

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  • Amazon EC2 Instance - m1.medium Ubuntu 12.04 - Started to crash three days ago

    - by Joy
    The environment: Amazon EC2 Instance - m1.medium Ubuntu 12.04 Apache 2.2.22 - Running a Drupal Site Using MySQL DB Server RAM info: ~$ free -gt total used free shared buffers cached Mem: 3 1 2 0 0 0 -/+ buffers/cache: 0 2 Swap: 0 0 0 Total: 3 1 2 Hard drive info: Filesystem Size Used Avail Use% Mounted on /dev/xvda1 7.9G 4.7G 2.9G 62% / udev 1.9G 8.0K 1.9G 1% /dev tmpfs 751M 180K 750M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1.9G 0 1.9G 0% /run/shm /dev/xvdb 394G 199M 374G 1% /mnt The problem About two days ago the site started failing becaue the MySQL server was shut down by Apache with the following message: kernel: [2963685.664359] [31716] 106 31716 226946 22748 0 0 0 mysqld kernel: [2963685.664730] Out of memory: Kill process 31716 (mysqld) score 23 or sacrifice child kernel: [2963685.664764] Killed process 31716 (mysqld) total-vm:907784kB, anon-rss:90992kB, file-rss:0kB kernel: [2963686.153608] init: mysql main process (31716) killed by KILL signal kernel: [2963686.169294] init: mysql main process ended, respawning That states that the VM was occupying 0.9GB, but my Ram has 2GB free, so 1GB was still left free. I understand that in Linux applications can allocate more memory than physically available. I don't know if this is the problme, it's the first time that it has started to happen. Obviously, the MySQL server tries to restart, but there's no memory for it apparently and it won't restart. Here is its error log: Plugin 'FEDERATED' is disabled. The InnoDB memory heap is disabled Mutexes and rw_locks use GCC atomic builtins Compressed tables use zlib 1.2.3.4 Initializing buffer pool, size = 128.0M InnoDB: mmap(137363456 bytes) failed; errno 12 Completed initialization of buffer pool Fatal error: cannot allocate memory for the buffer pool Plugin 'InnoDB' init function returned error. Plugin 'InnoDB' registration as a STORAGE ENGINE failed. Unknown/unsupported storage engine: InnoDB [ERROR] Aborting [Note] /usr/sbin/mysqld: Shutdown complete I simply restarted the Mysql service. About two hours later it happened again. I restarted it. Then it happened again 9 hours later. So then I thought of the MaxClients parameter of apache.conf, so I went to check it out. It was set at 150. I decided to drop it down to 60. As so: <IfModule mpm_prefork_module> ... MaxClients 60 </IfModule> <IfModule mpm_worker_module> ... MaxClients 60 </IfModule> <IfModule mpm_event_module> ... MaxClients 60 </IfModule> Once I did that, I had the apache2 service restart and it all went smoothly for 3/4 of a day. Since at night the MySQL service shut down once again, but this time it wasn't killed by the Apache2 service. Instead it called the OOM-Killer with the following message: kernel: [3104680.005312] mysqld invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0 kernel: [3104680.005351] [<ffffffff81119795>] oom_kill_process+0x85/0xb0 kernel: [3104680.548860] init: mysql main process (30821) killed by KILL signal Now I'm out of ideas. Some articles state that the ideal thing to do is change the kernel behaviour with the following (include it to the file /etc/sysctl.conf ) vm.overcommit_memory = 2 vm.overcommit_ratio = 80 So no overcommits will take place. I'm wondering if this is the way to go? Keep in mind I'm no server administrator, I have basic knowldege. Thanks a bunch in advance.

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  • stunnel crashing

    - by Jay
    I'm trying to use stunnel to secure a legacy application's communications. I can't seem to get it setup and working. Can anyone provide any hints where I'm going wrong? Here's what I'm trying to accomplish: A windows service on a client machine connects to a server on port 7000 using TCP. I'd like to encrypt the communication between client and server. Here's what I've tried: Created a new server that accepts ssl connections on port 7443. Got a certificate for the server and installed it. That seems to work with my test setup. Installed stunnel on my windows machine (version 7.43 from the distribution archive file). Installed libssl32.dll and libeay32.dll in the same directory as stunnel.exe ( from the openssl-0.9.8h-1 binary distribution). Installed it as a service using "stunnel -install" Configured stunnel as follows: debug=7 output=C:\p4\internal\Utility\Proxy\proxy.log service=Proxy taskbar=no [exchange] accept=7000 client=yes connect=proxy.blah.com:7443 I changed my hosts file to trick the old application into connecting through stunnel: server.blah.com 127.0.0.1 # when client looks up server it goes to stunnel proxy.blah.com IP-address-of-server.blah.com # stunnel connects to new server "server.blah.com" now resolves to the machine it's running on (i.e. stunnel). "proxy.blah.com" goes to the real server. stunnel should connect to the server. I start the stunnel service and try to connect. It looks like it's working but the stunnel service just shuts down with no message. 2010.04.19 13:16:21 LOG5[4924:3716]: stunnel 4.33 on x86-pc-mingw32-gnu with OpenSSL 0.9.8h 28 May 2008 2010.04.19 13:16:21 LOG5[4924:3716]: Threading:WIN32 SSL:ENGINE Sockets:SELECT,IPv6 2010.04.19 13:16:49 LOG5[4924:3748]: Service exchange accepted connection from 127.0.0.1:4134 2010.04.19 13:16:49 LOG6[4924:3748]: connect_blocking: connecting x.80.60.32:7443 2010.04.19 13:16:49 LOG5[4924:3748]: connect_blocking: connected x.80.60.32:7443 2010.04.19 13:16:49 LOG5[4924:3748]: Service exchange connected remote server from x.253.120.19:4135 2010.04.19 13:20:24 LOG5[3668:3856]: Reading configuration from file stunnel.conf 2010.04.19 13:20:24 LOG7[3668:3856]: Snagged 64 random bytes from C:/.rnd 2010.04.19 13:20:24 LOG7[3668:3856]: Wrote 1024 new random bytes to C:/.rnd 2010.04.19 13:20:24 LOG7[3668:3856]: RAND_status claims sufficient entropy for the PRNG 2010.04.19 13:20:24 LOG7[3668:3856]: PRNG seeded successfully 2010.04.19 13:20:24 LOG7[3668:3856]: SSL context initialized for service exchange 2010.04.19 13:20:24 LOG5[3668:3856]: Configuration successful 2010.04.19 13:20:24 LOG5[3668:3856]: No limit detected for the number of clients 2010.04.19 13:20:24 LOG7[3668:3856]: FD=312 in non-blocking mode 2010.04.19 13:20:24 LOG7[3668:3856]: Option SO_REUSEADDR set on accept socket 2010.04.19 13:20:24 LOG7[3668:3856]: Service exchange bound to 0.0.0.0:7000 2010.04.19 13:20:24 LOG7[3668:3856]: Service exchange opened FD=312 2010.04.19 13:20:24 LOG5[3668:3856]: stunnel 4.33 on x86-pc-mingw32-gnu with OpenSSL 0.9.8h 28 May 2008 2010.04.19 13:20:24 LOG5[3668:3856]: Threading:WIN32 SSL:ENGINE Sockets:SELECT,IPv6 2010.04.19 13:21:02 LOG7[3668:4556]: Service exchange accepted FD=372 from 127.0.0.1:4156 2010.04.19 13:21:02 LOG7[3668:4556]: Creating a new thread 2010.04.19 13:21:02 LOG7[3668:4556]: New thread created 2010.04.19 13:21:02 LOG7[3668:3756]: Service exchange started 2010.04.19 13:21:02 LOG7[3668:3756]: FD=372 in non-blocking mode 2010.04.19 13:21:02 LOG5[3668:3756]: Service exchange accepted connection from 127.0.0.1:4156 2010.04.19 13:21:02 LOG7[3668:3756]: FD=396 in non-blocking mode 2010.04.19 13:21:02 LOG6[3668:3756]: connect_blocking: connecting x.80.60.32:7443 2010.04.19 13:21:02 LOG7[3668:3756]: connect_blocking: s_poll_wait x.80.60.32:7443: waiting 10 seconds 2010.04.19 13:21:02 LOG5[3668:3756]: connect_blocking: connected x.80.60.32:7443 2010.04.19 13:21:02 LOG5[3668:3756]: Service exchange connected remote server from x.253.120.19:4157 2010.04.19 13:21:02 LOG7[3668:3756]: Remote FD=396 initialized 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): before/connect initialization 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write client hello A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read server hello A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read server certificate A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read server done A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write client key exchange A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write change cipher spec A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 write finished A 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 flush data 2010.04.19 13:21:02 LOG7[3668:3756]: SSL state (connect): SSLv3 read finished A The client thinks the connection is closed: No connection could be made because the target machine actively refused it 127.0.0.1:7000 at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.Sockets.Socket.Connect(EndPoint remoteEP) at Service.ConnUtility.Connect() Any suggestions?

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  • JBoss https on port other than 8080 not working

    - by MilindaD
    We have a server with two JBoss instances where one runs on 8080, the other on 8081. We need to have HTTPS enabled for the 8081 server, firstly we tried enabling https on the 8080 port instance by generating the keystore and editing the server.xml and it successfully worked. However when we tried the same thing for 8081 it did not, note that we removed https for the 8080 server first before enabling it for 8081. This is what was used for both server.xml for 8080 and 8081. The only difference was that the port was changed from 8080 to 8081 when trying to enable https for 8081 port instance. What am I doing wrong and what needs to be changed? NOTE : When I meant enabled for 8080 I meant when you visit https:// URL:8484 you will actually be visiting the 8080 port instance. However when ssl is enabled for 8081 and I visit https:// URL:8484 I get that the web page is unavailable. COMMENTLESS VERSION <Server> <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" /> <Listener className="org.apache.catalina.core.JasperListener" /> <Service name="jboss.web"> <!-- https --> <Connector port="8080" address="${jboss.bind.address}" maxThreads="350" maxHttpHeaderSize="8192" emptySessionPath="true" protocol="HTTP/1.1" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" compression="on" ompressableMimeType="text/html,text/css,text/javascript,application/json,text/xml,text/plain,application/x-javascript,application/javascript"/> <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" address="${jboss.bind.address}" keystoreFile="${jboss.server.home.dir}/conf/supun1.keystore" keystorePass="aaaaaa" truststoreFile="${jboss.server.home.dir}/conf/supun1.keystore" truststorePass="aaaaaa" /> <!-- https1 --> <Connector port="8009" address="${jboss.bind.address}" protocol="AJP/1.3" emptySessionPath="true" enableLookups="false" redirectPort="8443" /> <Engine name="jboss.web" defaultHost="localhost" jvmRoute="khms1"> <Realm className="org.jboss.web.tomcat.security.JBossSecurityMgrRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> <Host name="localhost" autoDeploy="false" deployOnStartup="false" deployXML="false" configClass="org.jboss.web.tomcat.security.config.JBossContextConfig" > <Valve className="org.jboss.web.tomcat.service.sso.ClusteredSingleSignOn" /> <Valve className="org.jboss.web.tomcat.service.jca.CachedConnectionValve" cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" transactionManagerObjectName="jboss:service=TransactionManager" /> </Host> </Engine> </Service> </Server> WITH COMMENTS VERSION <Server> <!--APR library loader. Documentation at /docs/apr.html --> <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" /> <!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html --> <Listener className="org.apache.catalina.core.JasperListener" /> <!-- Use a custom version of StandardService that allows the connectors to be started independent of the normal lifecycle start to allow web apps to be deployed before starting the connectors. --> <Service name="jboss.web"> <!-- A "Connector" represents an endpoint by which requests are received and responses are returned. Documentation at : Java HTTP Connector: /docs/config/http.html (blocking & non-blocking) Java AJP Connector: /docs/config/ajp.html APR (HTTP/AJP) Connector: /docs/apr.html Define a non-SSL HTTP/1.1 Connector on port 8080 --> <Connector port="8080" address="${jboss.bind.address}" maxThreads="350" maxHttpHeaderSize="8192" emptySessionPath="true" protocol="HTTP/1.1" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" compression="on" ompressableMimeType="text/html,text/css,text/javascript,application/json,text/xml,text/plain,application/x-javascript,application/javascript"/> <!-- Define a SSL HTTP/1.1 Connector on port 8443 This connector uses the JSSE configuration, when using APR, the connector should be using the OpenSSL style configuration described in the APR documentation --> <!-- <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" keystoreFile="${jboss.server.home.dir}/conf/zara.keystore" keystorePass="zara2010" clientAuth="false" sslProtocol="TLS" compression="on" /> --> <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" address="${jboss.bind.address}" keystoreFile="${jboss.server.home.dir}/conf/supun1.keystore" keystorePass="aaaaaa" truststoreFile="${jboss.server.home.dir}/conf/supun1.keystore" truststorePass="aaaaaa" /> <!-- Define an AJP 1.3 Connector on port 8009 --> <Connector port="8009" address="${jboss.bind.address}" protocol="AJP/1.3" emptySessionPath="true" enableLookups="false" redirectPort="8443" /> <Engine name="jboss.web" defaultHost="localhost" jvmRoute="khms1"> <!-- The JAAS based authentication and authorization realm implementation that is compatible with the jboss 3.2.x realm implementation. - certificatePrincipal : the class name of the org.jboss.security.auth.certs.CertificatePrincipal impl used for mapping X509[] cert chains to a Princpal. - allRolesMode : how to handle an auth-constraint with a role-name=*, one of strict, authOnly, strictAuthOnly + strict = Use the strict servlet spec interpretation which requires that the user have one of the web-app/security-role/role-name + authOnly = Allow any authenticated user + strictAuthOnly = Allow any authenticated user only if there are no web-app/security-roles --> <Realm className="org.jboss.web.tomcat.security.JBossSecurityMgrRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> <!-- A subclass of JBossSecurityMgrRealm that uses the authentication behavior of JBossSecurityMgrRealm, but overrides the authorization checks to use JACC permissions with the current java.security.Policy to determine authorized access. - allRolesMode : how to handle an auth-constraint with a role-name=*, one of strict, authOnly, strictAuthOnly + strict = Use the strict servlet spec interpretation which requires that the user have one of the web-app/security-role/role-name + authOnly = Allow any authenticated user + strictAuthOnly = Allow any authenticated user only if there are no web-app/security-roles <Realm className="org.jboss.web.tomcat.security.JaccAuthorizationRealm" certificatePrincipal="org.jboss.security.auth.certs.SubjectDNMapping" allRolesMode="authOnly" /> --> <Host name="localhost" autoDeploy="false" deployOnStartup="false" deployXML="false" configClass="org.jboss.web.tomcat.security.config.JBossContextConfig" > <!-- Uncomment to enable request dumper. This Valve "logs interesting contents from the specified Request (before processing) and the corresponding Response (after processing). It is especially useful in debugging problems related to headers and cookies." --> <!-- <Valve className="org.apache.catalina.valves.RequestDumperValve" /> --> <!-- Access logger --> <!-- <Valve className="org.apache.catalina.valves.AccessLogValve" prefix="localhost_access_log." suffix=".log" pattern="common" directory="${jboss.server.log.dir}" resolveHosts="false" /> --> <!-- Uncomment to enable single sign-on across web apps deployed to this host. Does not provide SSO across a cluster. If this valve is used, do not use the JBoss ClusteredSingleSignOn valve shown below. A new configuration attribute is available beginning with release 4.0.4: cookieDomain configures the domain to which the SSO cookie will be scoped (i.e. the set of hosts to which the cookie will be presented). By default the cookie is scoped to "/", meaning the host that presented it. Set cookieDomain to a wider domain (e.g. "xyz.com") to allow an SSO to span more than one hostname. --> <!-- <Valve className="org.apache.catalina.authenticator.SingleSignOn" /> --> <!-- Uncomment to enable single sign-on across web apps deployed to this host AND to all other hosts in the cluster. If this valve is used, do not use the standard Tomcat SingleSignOn valve shown above. Valve uses a JBossCache instance to support SSO credential caching and replication across the cluster. The JBossCache instance must be configured separately. By default, the valve shares a JBossCache with the service that supports HttpSession replication. See the "jboss-web-cluster-service.xml" file in the server/all/deploy directory for cache configuration details. Besides the attributes supported by the standard Tomcat SingleSignOn valve (see the Tomcat docs), this version also supports the following attributes: cookieDomain see above treeCacheName JMX ObjectName of the JBossCache MBean used to support credential caching and replication across the cluster. If not set, the default value is "jboss.cache:service=TomcatClusteringCache", the standard ObjectName of the JBossCache MBean used to support session replication. --> <Valve className="org.jboss.web.tomcat.service.sso.ClusteredSingleSignOn" /> <!-- Check for unclosed connections and transaction terminated checks in servlets/jsps. Important: The dependency on the CachedConnectionManager in META-INF/jboss-service.xml must be uncommented, too --> <Valve className="org.jboss.web.tomcat.service.jca.CachedConnectionValve" cachedConnectionManagerObjectName="jboss.jca:service=CachedConnectionManager" transactionManagerObjectName="jboss:service=TransactionManager" /> </Host> </Engine> </Service> </Server>

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  • Optimise Apache for EC2 micro instance

    - by Shiyu Sekam
    I'm running apache2 on a EC2 micro instance with ~600 mb RAM. The instance was running for almost a year without problems, but in the last weeks it just keeps crashing, because the server reached MaxClients. The server basically runs few websites, one wordpress blog(not often used), company website(most used) and 2 small sites, which are just internal. The database for the blog runs on RDS, so there's no Mysql running on this web server. When I came to the company, the server already was setup and is running apache + mod_php + prefork. We want to migrate that in the future to a nginx + php-fpm, but it still needs further testing. So for now I have to stick with the old setup. I also use CloudFlare DDOS protection in front of the server, because it was attacked a couple of the times in the last weeks. My company don't want to pay money for a better web server at this point, so I have to stick with the micro instance also. Additionally the code for the website we run is really bad and slow and sometimes a single page load can take up to 15 seconds. The whole website is dynamic and written in PHP, so caching isn't really an option here. It's a customized search for users. I've already turned off KeepAlive, which improved the performance a little bit. My prefork config looks like the following: StartServers 2 MinSpareServers 2 MaxSpareServers 5 ServerLimit 10 MaxClients 10 MaxRequestsPerChild 100 The server just becomes unresponsive after a while running and I've run the following command to see how many connections there are: netstat | grep http | wc -l 75 Trying to restart apache helps for a short moment, but after that a while the apache process(es) become unresponsive again. I've the following modules enabled(output of apache2ctl -M) Loaded Modules: core_module (static) log_config_module (static) logio_module (static) version_module (static) mpm_prefork_module (static) http_module (static) so_module (static) alias_module (shared) authz_host_module (shared) deflate_module (shared) dir_module (shared) expires_module (shared) mime_module (shared) negotiation_module (shared) php5_module (shared) rewrite_module (shared) setenvif_module (shared) ssl_module (shared) status_module (shared) Syntax OK apache2.conf # Security ServerTokens OS ServerSignature On TraceEnable On ServerName "web.example.com" ServerRoot "/etc/apache2" PidFile ${APACHE_PID_FILE} Timeout 30 KeepAlive off User www-data Group www-data AccessFileName .htaccess <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy all </Files> <Directory /> Options FollowSymLinks AllowOverride None </Directory> DefaultType none HostnameLookups Off ErrorLog /var/log/apache2/error.log LogLevel warn EnableSendfile On #Listen 80 Include /etc/apache2/mods-enabled/*.load Include /etc/apache2/mods-enabled/*.conf Include /etc/apache2/ports.conf LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %b" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent Include /etc/apache2/conf.d/*.conf Include /etc/apache2/sites-enabled/*.conf Vhost of main site <VirtualHost *:80> ServerName www.example.com ## Vhost docroot DocumentRoot /srv/www/jenkins/Web ## Directories, there should at least be a declaration for /srv/www/jenkins/Web <Directory /srv/www/jenkins/Web> AllowOverride All Order allow,deny Allow from all </Directory> ## Load additional static includes ## Logging ErrorLog /var/log/apache2/www.example.com.error.log LogLevel warn ServerSignature Off CustomLog /var/log/apache2/www.example.com.access.log combined ## Rewrite rules RewriteEngine On RewriteCond %{HTTP_HOST} !^www.example.com$ RewriteRule ^.*$ http://www.example.com%{REQUEST_URI} [R=301,L] ## Server aliases ServerAlias www.example.invalid ServerAlias example.com ## Custom fragment <Location /srv/www/jenkins/Web/library> Order Deny,Allow Deny from all </Location> <Files ~ "^\.(.+)"> Order deny,allow deny from all </Files> </VirtualHost>

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  • need assistance with my.cnf - 1500% CPU usage

    - by Alan Long
    I'm running into a few issues with our new database server. It is a HP G8 with 2 INTEL XEON E5-2650 processors and 32GB of ram. This server is dedicated as a MySQL server (5.1.69) for our intranet portal. I have been having issues with this server staying alive - I notice high CPU usage during certain times of day (8% ~ 1500%+) and see very low memory usage (7 ~ 15%) based on using the 'top' command. When the CPU usage passes 1000%, that is when the app usually dies. I'm trying to see what I'm doing wrong with the config file, hopefully one of the experts can chime in and let me know what they think. See below for my.cnf file: [mysqld] default-storage-engine=InnoDB datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock #user=mysql large-pages # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 max_connections=275 tmp_table_size=1G key_buffer_size=384M key_buffer=384M thread_cache_size=1024 long_query_time=5 low_priority_updates=1 max_heap_table_size=1G myisam_sort_buffer_size=8M concurrent_insert=2 table_cache=1024 sort_buffer_size=8M read_buffer_size=5M read_rnd_buffer_size=6M join_buffer_size=16M table_definition_cache=6k open_files_limit=8k slow_query_log #skip-name-resolve # Innodb Settings innodb_buffer_pool_size=18G innodb_thread_concurrency=0 innodb_log_file_size=1G innodb_log_buffer_size=16M innodb_flush_log_at_trx_commit=2 innodb_lock_wait_timeout=50 innodb_file_per_table #innodb_buffer_pool_instances=4 #eliminating double buffering innodb_flush_method = O_DIRECT flush_time=86400 innodb_additional_mem_pool_size=40M #innodb_io_capacity = 5000 #innodb_read_io_threads = 64 #innodb_write_io_threads = 64 # increase until threads_created doesnt grow anymore thread_cache=1024 query_cache_type=1 query_cache_limit=4M query_cache_size=256M # Try number of CPU's*2 for thread_concurrency thread_concurrency = 0 wait_timeout = 1800 connect_timeout = 10 interactive_timeout = 60 [mysqldump] max_allowed_packet=32M [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid log-slow-queries=/var/log/mysql/slow-queries.log long_query_time = 1 log-queries-not-using-indexes we connect to one database with 75 tables, the largest table has 1,150,000 entries and the second largest has 128,036 entries. I have also verified that our PHP queries are optimized as best as possible. Reference - MySQLtuner: >> MySQLTuner 1.2.0 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.69-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in InnoDB tables: 420M (Tables: 75) [!!] Total fragmented tables: 75 -------- Security Recommendations ------------------------------------------- [!!] User '[email protected]' has no password set. -------- Performance Metrics ------------------------------------------------- [--] Up for: 1h 14m 50s (8M q [1K qps], 705 conn, TX: 6B, RX: 892M) [--] Reads / Writes: 68% / 32% [--] Total buffers: 19.7G global + 35.2M per thread (275 max threads) [!!] Maximum possible memory usage: 29.1G (93% of installed RAM) [OK] Slow queries: 0% (472/8M) [OK] Highest usage of available connections: 66% (183/275) [OK] Key buffer size / total MyISAM indexes: 384.0M/91.0K [OK] Key buffer hit rate: 100.0% (173 cached / 0 reads) [OK] Query cache efficiency: 96.2% (7M cached / 7M selects) [!!] Query cache prunes per day: 553614 [OK] Sorts requiring temporary tables: 0% (3 temp sorts / 1K sorts) [!!] Temporary tables created on disk: 49% (3K on disk / 7K total) [OK] Thread cache hit rate: 74% (183 created / 705 connections) [OK] Table cache hit rate: 97% (231 open / 238 opened) [OK] Open file limit used: 0% (17/8K) [OK] Table locks acquired immediately: 100% (432K immediate / 432K locks) [OK] InnoDB data size / buffer pool: 420.9M/18.0G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce your overall MySQL memory footprint for system stability Increasing the query_cache size over 128M may reduce performance Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 256M) [see warning above] Thanks in advanced for your help!

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