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• ThickBox - update inside without redirect

  - by Alex Maslakov

  ASP.NET MVC and jQuery ThickBox. I show some content in ThickBox. It includes file upload form The view multi-media.apsx (it's strange, the this editor doesn't allow start the line with "<" in the code) form action="/upload/multi-media" method="post" enctype="multipart/form-data" label for="file"File name: input type="file" name="file" id="file" / input type="submit" value="Upload" / <% if (Model.Count > 0) { foreach (FileInfo mediaFile in Model) { <img width="100px" height="100px" src="<%: ResolveUrl("~/audio.png") %>" border="0" alt="<%: mediaFile.Name %>" / //................ After file upload I redirect to /upload/multi-media action and content shows in normal window, not in ThickBox. [ActionName("multi-media"), HttpPost] public ActionResult MultiMedia(HttpPostedFileBase file) { if (file.ContentLength > 0) { file.SaveAs(GenerateNewFileName(fullFileName)); return View("multi-media", model); } } How can I stay into ThickBox after file upload? I need show content in ThickBox all the time, even after the file upload.

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• SQL SERVER – Securing TRUNCATE Permissions in SQL Server

  - by pinaldave

  Download the Script of this article from here. On December 11, 2010, Vinod Kumar, a Databases & BI technology evangelist from Microsoft Corporation, graced Ahmedabad by spending some time with the Community during the Community Tech Days (CTD) event. As he was running through a few demos, Vinod asked the audience one of the most fundamental and common interview questions – “What is the difference between a DELETE and TRUNCATE?“ Ahmedabad SQL Server User Group Expert Nakul Vachhrajani has come up with excellent solutions of the same. I must congratulate Nakul for this excellent solution and as a encouragement to User Group member, I am publishing the same article over here. Nakul Vachhrajani is a Software Specialist and systems development professional with Patni Computer Systems Limited. He has functional experience spanning legacy code deprecation, system design, documentation, development, implementation, testing, maintenance and support of complex systems, providing business intelligence solutions, database administration, performance tuning, optimization, product management, release engineering, process definition and implementation. He has comprehensive grasp on Database Administration, Development and Implementation with MS SQL Server and C, C++, Visual C++/C#. He has about 6 years of total experience in information technology. Nakul is an member of the Ahmedabad and Gandhinagar SQL Server User Groups, and actively contributes to the community by actively participating in multiple forums and websites like SQLAuthority.com, BeyondRelational.com, SQLServerCentral.com and many others. Please note: The opinions expressed herein are Nakul own personal opinions and do not represent his employer’s view in anyway. All data from everywhere here on Earth go through a series of  four distinct operations, identified by the words: CREATE, READ, UPDATE and DELETE, or simply, CRUD. Putting in Microsoft SQL Server terms, is the process goes like this: INSERT, SELECT, UPDATE and DELETE/TRUNCATE. Quite a few interesting responses were received and evaluated live during the session. To summarize them, the most important similarity that came out was that both DELETE and TRUNCATE participate in transactions. The major differences (not all) that came out of the exercise were: DELETE: DELETE supports a WHERE clause DELETE removes rows from a table, row-by-row Because DELETE moves row-by-row, it acquires a row-level lock Depending upon the recovery model of the database, DELETE is a fully-logged operation. Because DELETE moves row-by-row, it can fire off triggers TRUNCATE: TRUNCATE does not support a WHERE clause TRUNCATE works by directly removing the individual data pages of a table TRUNCATE directly occupies a table-level lock. (Because a lock is acquired, and because TRUNCATE can also participate in a transaction, it has to be a logged operation) TRUNCATE is, therefore, a minimally-logged operation; again, this depends upon the recovery model of the database Triggers are not fired when TRUNCATE is used (because individual row deletions are not logged) Finally, Vinod popped the big homework question that must be critically analyzed: “We know that we can restrict a DELETE operation to a particular user, but how can we restrict the TRUNCATE operation to a particular user?” After returning home and having a nice cup of coffee, I noticed that my gray cells immediately started to work. Below was the result of my research. As what is always said, the devil is in the details. Upon looking at the Permissions section for the TRUNCATE statement in Books On Line, the following jumps right out: “The minimum permission required is ALTER on table_name. TRUNCATE TABLE permissions default to the table owner, members of the sysadmin fixed server role, and the db_owner and db_ddladmin fixed database roles, and are not transferable. However, you can incorporate the TRUNCATE TABLE statement within a module, such as a stored procedure, and grant appropriate permissions to the module using the EXECUTE AS clause.“ Now, what does this mean? Unlike DELETE, one cannot directly assign permissions to a user/set of users allowing or revoking TRUNCATE rights. However, there is a way to circumvent this. It is important to recall that in Microsoft SQL Server, database engine security surrounds the concept of a “securable”, which is any object like a table, stored procedure, trigger, etc. Rights are assigned to a principal on a securable. Refer to the image below (taken from the SQL Server Books On Line). urable”, which is any object like a table, stored procedure, trigger, etc. Rights are assigned to a principal on a securable. Refer to the image below (taken from the SQL Server Books On Line). SETTING UP THE ENVIRONMENT – (01A_Truncate Table Permissions.sql) Script Provided at the end of the article. By the end of this demo, one will be able to do all the CRUD operations, except the TRUNCATE, and the other will only be able to execute the TRUNCATE. All you will need for this test is any edition of SQL Server 2008. (With minor changes, these scripts can be made to work with SQL 2005.) We begin by creating the following: 1.       A test database 2.        Two database roles: associated logins and users 3.       Switch over to the test database and create a test table. Then, add some data into it. I am using row constructors, which is new to SQL 2008. Creating the modules that will be used to enforce permissions 1.       We have already created one of the modules that we will be assigning permissions to. That module is the table: TruncatePermissionsTest 2.       We will now create two stored procedures; one is for the DELETE operation and the other for the TRUNCATE operation. Please note that for all practical purposes, the end result is the same – all data from the table TruncatePermissionsTest is removed Assigning the permissions Now comes the most important part of the demonstration – assigning permissions. A permissions matrix can be worked out as under: To apply the security rights, we use the GRANT and DENY clauses, as under: That’s it! We are now ready for our big test! THE TEST (01B_Truncate Table Test Queries.sql) Script Provided at the end of the article. I will now need two separate SSMS connections, one with the login AllowedTruncate and the other with the login RestrictedTruncate. Running the test is simple; all that’s required is to run through the script – 01B_Truncate Table Test Queries.sql. What I will demonstrate here via screen-shots is the behavior of SQL Server when logged in as the AllowedTruncate user. There are a few other combinations than what are highlighted here. I will leave the reader the right to explore the behavior of the RestrictedTruncate user and these additional scenarios, as a form of self-study. 1.       Testing SELECT permissions 2.       Testing TRUNCATE permissions (Remember, “deny by default”?) 3.       Trying to circumvent security by trying to TRUNCATE the table using the stored procedure Hence, we have now proved that a user can indeed be assigned permissions to specifically assign TRUNCATE permissions. I also hope that the above has sparked curiosity towards putting some security around the probably “destructive” operations of DELETE and TRUNCATE. I would like to wish each and every one of the readers a very happy and secure time with Microsoft SQL Server. (Please find the scripts – 01A_Truncate Table Permissions.sql and 01B_Truncate Table Test Queries.sql that have been used in this demonstration. Please note that these scripts contain purely test-level code only. These scripts must not, at any cost, be used in the reader’s production environments). 01A_Truncate Table Permissions.sql /* ***************************************************************************************************************** Developed By          : Nakul Vachhrajani Functionality         : This demo is focused on how to allow only TRUNCATE permissions to a particular user How to Use            : 1. Run through, step-by-step through the sequence till Step 08 to create a test database 2. Switch over to the "Truncate Table Test Queries.sql" and execute it step-by-step in two different SSMS windows, one where you have logged in as 'RestrictedTruncate', and the other as 'AllowedTruncate' 3. Come back to "Truncate Table Permissions.sql" 4. Execute Step 10 to cleanup! Modifications         : December 13, 2010 - NAV - Updated to add a security matrix and improve code readability when applying security December 12, 2010 - NAV - Created ***************************************************************************************************************** */ -- Step 01: Create a new test database CREATE DATABASE TruncateTestDB GO USE TruncateTestDB GO -- Step 02: Add roles and users to demonstrate the security of the Truncate operation -- 2a. Create the new roles CREATE ROLE AllowedTruncateRole; GO CREATE ROLE RestrictedTruncateRole; GO -- 2b. Create new logins CREATE LOGIN AllowedTruncate WITH PASSWORD = 'truncate@2010', CHECK_POLICY = ON GO CREATE LOGIN RestrictedTruncate WITH PASSWORD = 'truncate@2010', CHECK_POLICY = ON GO -- 2c. Create new Users using the roles and logins created aboave CREATE USER TruncateUser FOR LOGIN AllowedTruncate WITH DEFAULT_SCHEMA = dbo GO CREATE USER NoTruncateUser FOR LOGIN RestrictedTruncate WITH DEFAULT_SCHEMA = dbo GO -- 2d. Add the newly created login to the newly created role sp_addrolemember 'AllowedTruncateRole','TruncateUser' GO sp_addrolemember 'RestrictedTruncateRole','NoTruncateUser' GO -- Step 03: Change over to the test database USE TruncateTestDB GO -- Step 04: Create a test table within the test databse CREATE TABLE TruncatePermissionsTest (Id INT IDENTITY(1,1), Name NVARCHAR(50)) GO -- Step 05: Populate the required data INSERT INTO TruncatePermissionsTest VALUES (N'Delhi'), (N'Mumbai'), (N'Ahmedabad') GO -- Step 06: Encapsulate the DELETE within another module CREATE PROCEDURE proc_DeleteMyTable WITH EXECUTE AS SELF AS DELETE FROM TruncateTestDB..TruncatePermissionsTest GO -- Step 07: Encapsulate the TRUNCATE within another module CREATE PROCEDURE proc_TruncateMyTable WITH EXECUTE AS SELF AS TRUNCATE TABLE TruncateTestDB..TruncatePermissionsTest GO -- Step 08: Apply Security /* *****************************SECURITY MATRIX*************************************** =================================================================================== Object                   | Permissions |                 Login |             | AllowedTruncate   |   RestrictedTruncate |             |User:NoTruncateUser|   User:TruncateUser =================================================================================== TruncatePermissionsTest  | SELECT,     |      GRANT        |      (Default) | INSERT,     |                   | | UPDATE,     |                   | | DELETE      |                   | -------------------------+-------------+-------------------+----------------------- TruncatePermissionsTest  | ALTER       |      DENY         |      (Default) -------------------------+-------------+----*/----------------+----------------------- proc_DeleteMyTable | EXECUTE | GRANT | DENY -------------------------+-------------+-------------------+----------------------- proc_TruncateMyTable | EXECUTE | DENY | GRANT -------------------------+-------------+-------------------+----------------------- *****************************SECURITY MATRIX*************************************** */ /* Table: TruncatePermissionsTest*/ GRANT SELECT, INSERT, UPDATE, DELETE ON TruncateTestDB..TruncatePermissionsTest TO NoTruncateUser GO DENY ALTER ON TruncateTestDB..TruncatePermissionsTest TO NoTruncateUser GO /* Procedure: proc_DeleteMyTable*/ GRANT EXECUTE ON TruncateTestDB..proc_DeleteMyTable TO NoTruncateUser GO DENY EXECUTE ON TruncateTestDB..proc_DeleteMyTable TO TruncateUser GO /* Procedure: proc_TruncateMyTable*/ DENY EXECUTE ON TruncateTestDB..proc_TruncateMyTable TO NoTruncateUser GO GRANT EXECUTE ON TruncateTestDB..proc_TruncateMyTable TO TruncateUser GO -- Step 09: Test --Switch over to the "Truncate Table Test Queries.sql" and execute it step-by-step in two different SSMS windows: --    1. one where you have logged in as 'RestrictedTruncate', and --    2. the other as 'AllowedTruncate' -- Step 10: Cleanup sp_droprolemember 'AllowedTruncateRole','TruncateUser' GO sp_droprolemember 'RestrictedTruncateRole','NoTruncateUser' GO DROP USER TruncateUser GO DROP USER NoTruncateUser GO DROP LOGIN AllowedTruncate GO DROP LOGIN RestrictedTruncate GO DROP ROLE AllowedTruncateRole GO DROP ROLE RestrictedTruncateRole GO USE MASTER GO DROP DATABASE TruncateTestDB GO 01B_Truncate Table Test Queries.sql /* ***************************************************************************************************************** Developed By          : Nakul Vachhrajani Functionality         : This demo is focused on how to allow only TRUNCATE permissions to a particular user How to Use            : 1. Switch over to this from "Truncate Table Permissions.sql", Step #09 2. Execute this step-by-step in two different SSMS windows a. One where you have logged in as 'RestrictedTruncate', and b. The other as 'AllowedTruncate' 3. Return back to "Truncate Table Permissions.sql" 4. Execute Step 10 to cleanup! Modifications         : December 12, 2010 - NAV - Created ***************************************************************************************************************** */ -- Step 09A: Switch to the test database USE TruncateTestDB GO -- Step 09B: Ensure that we have valid data SELECT * FROM TruncatePermissionsTest GO -- (Expected: Following error will occur if logged in as "AllowedTruncate") -- Msg 229, Level 14, State 5, Line 1 -- The SELECT permission was denied on the object 'TruncatePermissionsTest', database 'TruncateTestDB', schema 'dbo'. --Step 09C: Attempt to Truncate Data from the table without using the stored procedure TRUNCATE TABLE TruncatePermissionsTest GO -- (Expected: Following error will occur) --  Msg 1088, Level 16, State 7, Line 2 --  Cannot find the object "TruncatePermissionsTest" because it does not exist or you do not have permissions. -- Step 09D:Regenerate Test Data INSERT INTO TruncatePermissionsTest VALUES (N'London'), (N'Paris'), (N'Berlin') GO -- (Expected: Following error will occur if logged in as "AllowedTruncate") -- Msg 229, Level 14, State 5, Line 1 -- The INSERT permission was denied on the object 'TruncatePermissionsTest', database 'TruncateTestDB', schema 'dbo'. --Step 09E: Attempt to Truncate Data from the table using the stored procedure EXEC proc_TruncateMyTable GO -- (Expected: Will execute successfully with 'AllowedTruncate' user, will error out as under with 'RestrictedTruncate') -- Msg 229, Level 14, State 5, Procedure proc_TruncateMyTable, Line 1 -- The EXECUTE permission was denied on the object 'proc_TruncateMyTable', database 'TruncateTestDB', schema 'dbo'. -- Step 09F:Regenerate Test Data INSERT INTO TruncatePermissionsTest VALUES (N'Madrid'), (N'Rome'), (N'Athens') GO --Step 09G: Attempt to Delete Data from the table without using the stored procedure DELETE FROM TruncatePermissionsTest GO -- (Expected: Following error will occur if logged in as "AllowedTruncate") -- Msg 229, Level 14, State 5, Line 2 -- The DELETE permission was denied on the object 'TruncatePermissionsTest', database 'TruncateTestDB', schema 'dbo'. -- Step 09H:Regenerate Test Data INSERT INTO TruncatePermissionsTest VALUES (N'Spain'), (N'Italy'), (N'Greece') GO --Step 09I: Attempt to Delete Data from the table using the stored procedure EXEC proc_DeleteMyTable GO -- (Expected: Following error will occur if logged in as "AllowedTruncate") -- Msg 229, Level 14, State 5, Procedure proc_DeleteMyTable, Line 1 -- The EXECUTE permission was denied on the object 'proc_DeleteMyTable', database 'TruncateTestDB', schema 'dbo'. --Step 09J: Close this SSMS window and return back to "Truncate Table Permissions.sql" Thank you Nakul to take up the challenge and prove that Ahmedabad and Gandhinagar SQL Server User Group has talent to solve difficult problems. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Best Practices, Pinal Dave, Readers Contribution, Readers Question, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Security, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Abstracting functionality

  - by Ralf Westphal

  Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/22/abstracting-functionality.aspxWhat is more important than data? Functionality. Yes, I strongly believe we should switch to a functionality over data mindset in programming. Or actually switch back to it. Focus on functionality Functionality once was at the core of software development. Back when algorithms were the first thing you heard about in CS classes. Sure, data structures, too, were important - but always from the point of view of algorithms. (Niklaus Wirth gave one of his books the title “Algorithms + Data Structures” instead of “Data Structures + Algorithms” for a reason.) The reason for the focus on functionality? Firstly, because software was and is about doing stuff. Secondly because sufficient performance was hard to achieve, and only thirdly memory efficiency. But then hardware became more powerful. That gave rise to a new mindset: object orientation. And with it functionality was devalued. Data took over its place as the most important aspect. Now discussions revolved around structures motivated by data relationships. (John Beidler gave his book the title “Data Structures and Algorithms: An Object Oriented Approach” instead of the other way around for a reason.) Sure, this data could be embellished with functionality. But nevertheless functionality was second. When you look at (domain) object models what you mostly find is (domain) data object models. The common object oriented approach is: data aka structure over functionality. This is true even for the most modern modeling approaches like Domain Driven Design. Look at the literature and what you find is recommendations on how to get data structures right: aggregates, entities, value objects. I´m not saying this is what object orientation was invented for. But I´m saying that´s what I happen to see across many teams now some 25 years after object orientation became mainstream through C++, Delphi, and Java. But why should we switch back? Because software development cannot become truly agile with a data focus. The reason for that lies in what customers need first: functionality, behavior, operations. To be clear, that´s not why software is built. The purpose of software is to be more efficient than the alternative. Money mainly is spent to get a certain level of quality (e.g. performance, scalability, security etc.). But without functionality being present, there is nothing to work on the quality of. What customers want is functionality of a certain quality. ASAP. And tomorrow new functionality needs to be added, existing functionality needs to be changed, and quality needs to be increased. No customer ever wanted data or structures. Of course data should be processed. Data is there, data gets generated, transformed, stored. But how the data is structured for this to happen efficiently is of no concern to the customer. Ask a customer (or user) whether she likes the data structured this way or that way. She´ll say, “I don´t care.” But ask a customer (or user) whether he likes the functionality and its quality this way or that way. He´ll say, “I like it” (or “I don´t like it”). Build software incrementally From this very natural focus of customers and users on functionality and its quality follows we should develop software incrementally. That´s what Agility is about. Deliver small increments quickly and often to get frequent feedback. That way less waste is produced, and learning can take place much easier (on the side of the customer as well as on the side of developers). An increment is some added functionality or quality of functionality.[1] So as it turns out, Agility is about functionality over whatever. But software developers’ thinking is still stuck in the object oriented mindset of whatever over functionality. Bummer. I guess that (at least partly) explains why Agility always hits a glass ceiling in projects. It´s a clash of mindsets, of cultures. Driving software development by demanding small increases in functionality runs against thinking about software as growing (data) structures sprinkled with functionality. (Excuse me, if this sounds a bit broad-brush. But you get my point.) The need for abstraction In the end there need to be data structures. Of course. Small and large ones. The phrase functionality over data does not deny that. It´s not functionality instead of data or something. It´s just over, i.e. functionality should be thought of first. It´s a tad more important. It´s what the customer wants. That´s why we need a way to design functionality. Small and large. We need to be able to think about functionality before implementing it. We need to be able to reason about it among team members. We need to be able to communicate our mental models of functionality not just by speaking about them, but also on paper. Otherwise reasoning about it does not scale. We learned thinking about functionality in the small using flow charts, Nassi-Shneiderman diagrams, pseudo code, or UML sequence diagrams. That´s nice and well. But it does not scale. You can use these tools to describe manageable algorithms. But it does not work for the functionality triggered by pressing the “1-Click Order” on an amazon product page for example. There are several reasons for that, I´d say. Firstly, the level of abstraction over code is negligible. It´s essentially non-existent. Drawing a flow chart or writing pseudo code or writing actual code is very, very much alike. All these tools are about control flow like code is.[2] In addition all tools are computationally complete. They are about logic which is expressions and especially control statements. Whatever you code in Java you can fully (!) describe using a flow chart. And then there is no data. They are about control flow and leave out the data altogether. Thus data mostly is assumed to be global. That´s shooting yourself in the foot, as I hope you agree. Even if it´s functionality over data that does not mean “don´t think about data”. Right to the contrary! Functionality only makes sense with regard to data. So data needs to be in the picture right from the start - but it must not dominate the thinking. The above tools fail on this. Bottom line: So far we´re unable to reason in a scalable and abstract manner about functionality. That´s why programmers are so driven to start coding once they are presented with a problem. Programming languages are the only tool they´ve learned to use to reason about functional solutions. Or, well, there might be exceptions. Mathematical notation and SQL may have come to your mind already. Indeed they are tools on a higher level of abstraction than flow charts etc. That´s because they are declarative and not computationally complete. They leave out details - in order to deliver higher efficiency in devising overall solutions. We can easily reason about functionality using mathematics and SQL. That´s great. Except for that they are domain specific languages. They are not general purpose. (And they don´t scale either, I´d say.) Bummer. So to be more precise we need a scalable general purpose tool on a higher than code level of abstraction not neglecting data. Enter: Flow Design. Abstracting functionality using data flows I believe the solution to the problem of abstracting functionality lies in switching from control flow to data flow. Data flow very naturally is not about logic details anymore. There are no expressions and no control statements anymore. There are not even statements anymore. Data flow is declarative by nature. With data flow we get rid of all the limiting traits of former approaches to modeling functionality. In addition, nomen est omen, data flows include data in the functionality picture. With data flows, data is visibly flowing from processing step to processing step. Control is not flowing. Control is wherever it´s needed to process data coming in. That´s a crucial difference and needs some rewiring in your head to be fully appreciated.[2] Since data flows are declarative they are not the right tool to describe algorithms, though, I´d say. With them you don´t design functionality on a low level. During design data flow processing steps are black boxes. They get fleshed out during coding. Data flow design thus is more coarse grained than flow chart design. It starts on a higher level of abstraction - but then is not limited. By nesting data flows indefinitely you can design functionality of any size, without losing sight of your data. Data flows scale very well during design. They can be used on any level of granularity. And they can easily be depicted. Communicating designs using data flows is easy and scales well, too. The result of functional design using data flows is not algorithms (too low level), but processes. Think of data flows as descriptions of industrial production lines. Data as material runs through a number of processing steps to be analyzed, enhances, transformed. On the top level of a data flow design might be just one processing step, e.g. “execute 1-click order”. But below that are arbitrary levels of flows with smaller and smaller steps. That´s not layering as in “layered architecture”, though. Rather it´s a stratified design à la Abelson/Sussman. Refining data flows is not your grandpa´s functional decomposition. That was rooted in control flows. Refining data flows does not suffer from the limits of functional decomposition against which object orientation was supposed to be an antidote. Summary I´ve been working exclusively with data flows for functional design for the past 4 years. It has changed my life as a programmer. What once was difficult is now easy. And, no, I´m not using Clojure or F#. And I´m not a async/parallel execution buff. Designing the functionality of increments using data flows works great with teams. It produces design documentation which can easily be translated into code - in which then the smallest data flow processing steps have to be fleshed out - which is comparatively easy. Using a systematic translation approach code can mirror the data flow design. That way later on the design can easily be reproduced from the code if need be. And finally, data flow designs play well with object orientation. They are a great starting point for class design. But that´s a story for another day. To me data flow design simply is one of the missing links of systematic lightweight software design. There are also other artifacts software development can produce to get feedback, e.g. process descriptions, test cases. But customers can be delighted more easily with code based increments in functionality. ? No, I´m not talking about the endless possibilities this opens for parallel processing. Data flows are useful independently of multi-core processors and Actor-based designs. That´s my whole point here. Data flows are good for reasoning and evolvability. So forget about any special frameworks you might need to reap benefits from data flows. None are necessary. Translating data flow designs even into plain of Java is possible. ?

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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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• Is there any alternate for applying Group Policy in AD LDS

  - by rajeevrautela

  Hi All, We can apply Group Level policy in AD DS, similarily is there any mechanism for applying Group level policy in AD LDS?

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• Low framerate on background apps

  - by user1698923

  My problem is that when a game is running in the foreground, in Full Screen mode, any applications on my second monitor (such as youtube videos, videos, not app specific) drop their frame-rate to about 2-3 FPS. It seems like some sort of power management option that I can't track down. As far as I can tell, it's not due to the GPU not being able to keep up. For instance, my PC can play League of Legends at about 280FPS when the framerate is uncapped. If i cap it at 60FPS using the in-game option, it has no affect on the performance of the background app. Summary Operating System Windows 8 Pro 64-bit CPU Intel Core i7 3820 @ 3.60GHz 42 °C Sandy Bridge-E 32nm Technology RAM 12.0GB Triple-Channel DDR3 @ 533MHz (7-7-7-20) Motherboard Gigabyte Technology Co., Ltd. X79-UD3 (SOCKET 0) 37 °C Graphics DELL U2713HM (2560x1440@59Hz) DELL U2713HM (2560x1440@59Hz) 1280MB NVIDIA GeForce GTX 570 (Gigabyte) 58 °C Hard Drives 212GB Volume0 (RAID) 1863GB Western Digital WDC WD20EARS-00MVWB0 (SATA) 36 °C 1863GB Western Digital WDC WD20EARS-00MVWB0 (SATA) 34 °C Optical Drives No optical disk drives detected Audio ASUS Xonar Essence STX Audio Device Operating System Windows 8 Pro 64-bit Computer type: Desktop Graphics Monitor 1 Name DELL U2713HM on NVIDIA GeForce GTX 570 Current Resolution 2560x1440 pixels Work Resolution 2560x1400 pixels State Enabled, Output devices support Multiple displays Extended, Secondary, Enabled Monitor Width 2560 Monitor Height 1440 Monitor BPP 32 bits per pixel Monitor Frequency 59 Hz Device \\.\DISPLAY4\Monitor0 Monitor 2 Name DELL U2713HM on NVIDIA GeForce GTX 570 Current Resolution 2560x1440 pixels Work Resolution 2560x1400 pixels State Enabled, Output devices support Multiple displays Extended, Primary, Enabled Monitor Width 2560 Monitor Height 1440 Monitor BPP 32 bits per pixel Monitor Frequency 59 Hz Device \\.\DISPLAY5\Monitor0 NVIDIA GeForce GTX 570 Manufacturer NVIDIA Model GeForce GTX 570 GPU GF110 Device ID 10DE-1086 Revision A2 Subvendor Gigabyte (1458) Series GeForce GTX 500 Current Performance Level Level 3 Current GPU Clock 845 MHz Current Memory Clock 1900 MHz Current Shader Clock 1690 MHz Voltage 0.988 V Technology 40 nm Die Size 520 mm² Release Date Dec 07, 2010 DirectX Support 11.0 OpenGL Support 5.0 Bus Interface PCI Express x16 Temperature 57 °C Driver version 9.18.13.2018 BIOS Version 70.10.55.00.01 ROPs 40 Shaders 512 unified Memory Type GDDR5 Memory 1280 MB Bus Width 64x5 (320 bit) Filtering Modes 16x Anisotropic Noise Level Moderate Max Power Draw 219 Watts Count of performance levels : 3 Level 1 - "Default" GPU Clock 50 MHz Memory Clock 135 MHz Shader Clock 101 MHz Level 2 - "2D Desktop" GPU Clock 405 MHz Memory Clock 324 MHz Shader Clock 810 MHz Level 3 - "3D Applications" GPU Clock 845 MHz Memory Clock 1900 MHz Shader Clock 1690 MHz Things I've tried: 1) Updating the graphics driver 2) Setting windows power mode to High Performance 3) Reset Nvidia Global Performance settings to default

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• I flashed my DS4700 with a 7 series firmware, now my DS4300 cannot read the disks I moved to that lo

  - by Daniel Hoeving

  In preparation for adding a number of 1Tb SATA disks to our DS4700 I flashed the controller firmware from a 6 series (which only supports up to 2Tb logical drives) to a 7 series (which supports larger than 2Tb logical drives). Attached to this DS4700 was a EXP710 expansion drawer that we had planned to migrate out to our co-location to allieviate the storage issues we were having there. Unfortunately these two projects were planned in isolation to one another so I was at the time unaware of the issue that this would cause. Prior to migrating the drawer I was reading the "IBM TotalStorage DS4000 EXP700 and EXP710 Storage Expansion EnclosuresInstallation, User’s, and Maintenance Guide" and discovered this: Controller firmware 6.xx or earlier has a different metadata (DACstore) data structure than controller firmware 7.xx.xx.xx. Metadata consists of the array and logical drive configuration data. These two metadata data structures are not interchangeable. When powered up and in Optimal state, the storage subsystem with controller firmware level 7.xx.xx.xx can convert the metadata from the drives configured in storage subsystems with controller firmware level 6.xx or earlier to controller firmware level 7.xx.xx.xx metadata data structure. However, the storage subsystem with controller firmware level 6.xx or earlier cannot read the metadata from the drives configured in storage subsystems with controller firmware level 7.xx.xx.xx or later. I had assumed that if I deleted the logical drives and array information on the EXP710 prior to migrating it to the DS4300 (6.60.22 firmware) this would satisfy the above, unfortunately I was wrong. So my question is a) Is it possible to restore the DAC information to its factory settings, b) What tool(s) would I use to accomplish this, or c) is this a lost cause? Daniel.

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• Are Windows Domain Service Accounts Really Necessary?

  - by Zach Bonham

  One of the biggest problems we have in automating application deployments is the idea that running IIS AppPools and Windows Services under domain service accounts is a 'best practice'. Unfortunately, this best practice sometimes causes deployment headaches in that either we need to provision a new domain level service account quickly, or once we have the account, we now need to manage the account credentials. I had a great conversation about not making domain level service accounts a requirement and effectively taking one of two approaches: Secure at the node level using machine account(domain\machine$) and add the node to appropriate ActiveDirectory/Sql groups/roles Create local app specific accounts on each machine (machine\myapp) and add that account to appropriate ActiveDirectory/Sql groups/roles (the password here can change per deployment, it doesn't need to be stored) In both cases, it seems that its easier to manage either adding an account to appropriate group/role, or even stand up new, local account, than it is to have to provision a new domain level account and manage those credentials. This would hopefully ease the management burden on ActiveDirectory, Sql Server and Operations teams as there would be no more password management. We've not actually been able to implement this in practice yet. I am coming from a development background, so I'm curious as to how many ways this approach could go wrong? Can we really get rid of domain level service accounts with this direction? I'd appreciate any thoughts from anyone who has taken this path! Thanks! Zach

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• Inconsistent black levels in windows 7 media center

  - by James G

  I've got a HTPC running windows 7 64bit, hooked up to a Samsung LCD TV. My problem is different types of video are displaying different black levels on the TV. When I play a bluray through Arcsoft Total Media Theater I have to set the "HDMI Black Level" to "normal" in the TV picture options menu. When I play recorded TV through WMC I have to set it to "low" otherwise the black colors on the video are washed out and grey. Is there any way to configure the system so all videos are displayed with the same black level? The hdmi black level setting is deep in Samsung's menus so it's becoming a chore to keep switching it everytime I watch a different type of video. I'm using an ATI 4670 graphics card with HDMI output going straight to the TV. In the ATI catalyst control center I've got pixel format set to RGB 4:4:4 (Full RGB) since the TV wont allow me to change the HDMI black level if I choose one of the other settings.

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• Degraded RAID5 and no md superblock on one of remaining drive

  - by ark1214

  This is actually on a QNAP TS-509 NAS. The RAID is basically a Linux RAID. The NAS was configured with RAID 5 with 5 drives (/md0 with /dev/sd[abcde]3). At some point, /dev/sde failed and drive was replaced. While rebuilding (and not completed), the NAS rebooted itself and /dev/sdc dropped out of the array. Now the array can't start because essentially 2 drives have dropped out. I disconnected /dev/sde and hoped that /md0 can resume in degraded mode, but no luck.. Further investigation shows that /dev/sdc3 has no md superblock. The data should be good since the array was unable to assemble after /dev/sdc dropped off. All the searches I done showed how to reassemble the array assuming 1 bad drive. But I think I just need to restore the superblock on /dev/sdc3 and that should bring the array up to a degraded mode which will allow me to backup data and then proceed with rebuilding with adding /dev/sde. Any help would be greatly appreciated. mdstat does not show /dev/md0 # cat /proc/mdstat Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] [multipath] md5 : active raid1 sdd2[2](S) sdc2[3](S) sdb2[1] sda2[0] 530048 blocks [2/2] [UU] md13 : active raid1 sdd4[3] sdc4[2] sdb4[1] sda4[0] 458880 blocks [5/4] [UUUU_] bitmap: 40/57 pages [160KB], 4KB chunk md9 : active raid1 sdd1[3] sdc1[2] sdb1[1] sda1[0] 530048 blocks [5/4] [UUUU_] bitmap: 33/65 pages [132KB], 4KB chunk mdadm show /dev/md0 is still there # mdadm --examine --scan ARRAY /dev/md9 level=raid1 num-devices=5 UUID=271bf0f7:faf1f2c2:967631a4:3c0fa888 ARRAY /dev/md5 level=raid1 num-devices=2 UUID=0d75de26:0759d153:5524b8ea:86a3ee0d spares=2 ARRAY /dev/md0 level=raid5 num-devices=5 UUID=ce3e369b:4ff9ddd2:3639798a:e3889841 ARRAY /dev/md13 level=raid1 num-devices=5 UUID=7384c159:ea48a152:a1cdc8f2:c8d79a9c With /dev/sde removed, here is the mdadm examine output showing sdc3 has no md superblock # mdadm --examine /dev/sda3 /dev/sda3: Magic : a92b4efc Version : 00.90.00 UUID : ce3e369b:4ff9ddd2:3639798a:e3889841 Creation Time : Sat Dec 8 15:01:19 2012 Raid Level : raid5 Used Dev Size : 1463569600 (1395.77 GiB 1498.70 GB) Array Size : 5854278400 (5583.08 GiB 5994.78 GB) Raid Devices : 5 Total Devices : 4 Preferred Minor : 0 Update Time : Sat Dec 8 15:06:17 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : d9e9ff0e - correct Events : 0.394 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 0 8 3 0 active sync /dev/sda3 0 0 8 3 0 active sync /dev/sda3 1 1 8 19 1 active sync /dev/sdb3 2 2 8 35 2 active sync /dev/sdc3 3 3 8 51 3 active sync /dev/sdd3 4 4 0 0 4 faulty removed [~] # mdadm --examine /dev/sdb3 /dev/sdb3: Magic : a92b4efc Version : 00.90.00 UUID : ce3e369b:4ff9ddd2:3639798a:e3889841 Creation Time : Sat Dec 8 15:01:19 2012 Raid Level : raid5 Used Dev Size : 1463569600 (1395.77 GiB 1498.70 GB) Array Size : 5854278400 (5583.08 GiB 5994.78 GB) Raid Devices : 5 Total Devices : 4 Preferred Minor : 0 Update Time : Sat Dec 8 15:06:17 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : d9e9ff20 - correct Events : 0.394 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 1 8 19 1 active sync /dev/sdb3 0 0 8 3 0 active sync /dev/sda3 1 1 8 19 1 active sync /dev/sdb3 2 2 8 35 2 active sync /dev/sdc3 3 3 8 51 3 active sync /dev/sdd3 4 4 0 0 4 faulty removed [~] # mdadm --examine /dev/sdc3 mdadm: No md superblock detected on /dev/sdc3. [~] # mdadm --examine /dev/sdd3 /dev/sdd3: Magic : a92b4efc Version : 00.90.00 UUID : ce3e369b:4ff9ddd2:3639798a:e3889841 Creation Time : Sat Dec 8 15:01:19 2012 Raid Level : raid5 Used Dev Size : 1463569600 (1395.77 GiB 1498.70 GB) Array Size : 5854278400 (5583.08 GiB 5994.78 GB) Raid Devices : 5 Total Devices : 4 Preferred Minor : 0 Update Time : Sat Dec 8 15:06:17 2012 State : active Active Devices : 4 Working Devices : 4 Failed Devices : 1 Spare Devices : 0 Checksum : d9e9ff44 - correct Events : 0.394 Layout : left-symmetric Chunk Size : 64K Number Major Minor RaidDevice State this 3 8 51 3 active sync /dev/sdd3 0 0 8 3 0 active sync /dev/sda3 1 1 8 19 1 active sync /dev/sdb3 2 2 8 35 2 active sync /dev/sdc3 3 3 8 51 3 active sync /dev/sdd3 4 4 0 0 4 faulty removed fdisk output shows /dev/sdc3 partition is still there. [~] # fdisk -l Disk /dev/sdx: 128 MB, 128057344 bytes 8 heads, 32 sectors/track, 977 cylinders Units = cylinders of 256 * 512 = 131072 bytes Device Boot Start End Blocks Id System /dev/sdx1 1 8 1008 83 Linux /dev/sdx2 9 440 55296 83 Linux /dev/sdx3 441 872 55296 83 Linux /dev/sdx4 873 977 13440 5 Extended /dev/sdx5 873 913 5232 83 Linux /dev/sdx6 914 977 8176 83 Linux Disk /dev/sda: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sda1 * 1 66 530113+ 83 Linux /dev/sda2 67 132 530145 82 Linux swap / Solaris /dev/sda3 133 182338 1463569695 83 Linux /dev/sda4 182339 182400 498015 83 Linux Disk /dev/sda4: 469 MB, 469893120 bytes 2 heads, 4 sectors/track, 114720 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/sda4 doesn't contain a valid partition table Disk /dev/sdb: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 * 1 66 530113+ 83 Linux /dev/sdb2 67 132 530145 82 Linux swap / Solaris /dev/sdb3 133 182338 1463569695 83 Linux /dev/sdb4 182339 182400 498015 83 Linux Disk /dev/sdc: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdc1 1 66 530125 83 Linux /dev/sdc2 67 132 530142 83 Linux /dev/sdc3 133 182338 1463569693 83 Linux /dev/sdc4 182339 182400 498012 83 Linux Disk /dev/sdd: 2000.3 GB, 2000398934016 bytes 255 heads, 63 sectors/track, 243201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdd1 1 66 530125 83 Linux /dev/sdd2 67 132 530142 83 Linux /dev/sdd3 133 243138 1951945693 83 Linux /dev/sdd4 243139 243200 498012 83 Linux Disk /dev/md9: 542 MB, 542769152 bytes 2 heads, 4 sectors/track, 132512 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/md9 doesn't contain a valid partition table Disk /dev/md5: 542 MB, 542769152 bytes 2 heads, 4 sectors/track, 132512 cylinders Units = cylinders of 8 * 512 = 4096 bytes Disk /dev/md5 doesn't contain a valid partition table

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• LACP : Cisco ASA 5515 & Switch ProCurve 2920

  - by user979276

  I've two ASAs 5515 connected in failover Active/Stand by (on Gi0/5) My two ASAs are connected to two Switch ProCurve 2920 to have HA if something happens. So I plug something like that (don't pay attention to the arrows) : So one the ASA, I created a Port-Channel like that : interface GigabitEthernet0/0 nameif outside security-level 0 ip address 192.168.1.3 255.255.255.0 standby 192.168.1.4 ! interface GigabitEthernet0/1 speed 1000 duplex full channel-group 1 mode passive no nameif no security-level no ip address ! interface GigabitEthernet0/2 speed 1000 duplex full channel-group 1 mode passive no nameif no security-level no ip address ! interface Port-channel1.1 vlan 1 nameif inside security-level 100 ip address 192.168.8.1 255.255.255.0 standby 192.168.8.2 ! interface Port-channel1.10 vlan 10 nameif guest security-level 50 ip address 172.16.100.2 255.255.255.224 standby 172.16.100.3 ! interface Port-channel1.16 vlan 16 nameif dmz security-level 50 ip address 192.168.16.1 255.255.255.0 standby 192.168.16.2 On the switch, I created a trunk LACP capable with the port 1 and 2 on each switch, force the speed to 1000 and put the port un full duplex mode. BUT this is not working... I tried many things and I can't make it work. In this configuration, I can't ping anything between my ASA and my Switch (or any object connected). Here what I get on my ASA : Channel group 1 LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State ----------------------------------------------------------------------------- Gi0/2 SP not-bndl 32768 0x1 0x1 0x3 0xc Gi0/1 FP not-bndl 32768 0x1 0x1 0x2 0x6 And on the Switchs : PORT LACP TRUNK PORT LACP LACP NUMB ENABLED GROUP STATUS PARTNER STATUS ----- ------- ----- ------ ------- ------ 1 Active trk1 Broken Yes Failure 2 Active trk1 Broken Yes Failure If I change the Cisco interface to LACP mode On, I can ping the switch from the ASA but nothing other objects conneted on the switch. If I look at the statut of LACP on the switch I see this : PORT LACP TRUNK PORT LACP LACP NUMB ENABLED GROUP STATUS PARTNER STATUS ----- ------- ----- ------ ------- ------ 1 Active trk1 Up No Success 2 Active trk1 Up No Success I don't have any clue on what's going on so If someone have any idea and help me on this, it would be great ! Feel free to ask me anything if you need any more information ! Thanks a lot !

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• Bacula virtual backup job doesn't run, no output?

  - by Zoredache

  I am trying to get Virtual Backups working, but when I try to run a virtual backup job, it appears to get created, but then never seems to actually run. I have a full, and a couple incremental backups. status director JobId Level Files Bytes Status Finished Name ==================================================================== 1283 Full 10,565 1.963 G OK 21-Dec-12 09:47 nms-Job 1284 Incr 314 129.6 M OK 21-Dec-12 09:49 nms-Job 1285 Incr 230 147.2 M OK 21-Dec-12 09:51 nms-Job 1288 Incr 525 138.8 M OK 21-Dec-12 11:25 nms-Job I attempt to start a job from bconsole like this. *run job=nms-Job level=VirtualFull Using Catalog "MySQL" Run Backup job JobName: nms-Job Level: VirtualFull Client: nms-FileDaemon FileSet: nms-FileSet Pool: nms-pool (From Job resource) Storage: File_d1 (From Pool resource) When: 2012-12-21 13:07:54 Priority: 10 OK to run? (yes/mod/no): Job queued. JobId=1291 Then my new job, just sits there, doing nothing. The JobStatus shows that the job was created, but it appears to never run? All the full, and incremental backups are terminating normally. *llist jobid=1291 JobId: 1,291 Job: nms-Job.2012-12-21_13.07.56_07 Name: nms-Job PurgedFiles: 0 Type: B Level: F ClientId: 4 Name: nms-FileDaemon JobStatus: C SchedTime: 2012-12-21 13:07:54 StartTime: 2012-12-21 13:07:56 EndTime: 0000-00-00 00:00:00 RealEndTime: 0000-00-00 00:00:00 JobTDate: 1,356,124,076 VolSessionId: 0 VolSessionTime: 0 JobFiles: 0 JobErrors: 0 JobMissingFiles: 0 PoolId: 19 PooLname: nms-pool PriorJobId: 0 FileSetId: 11 FileSet: nms-FileSet I am getting very frustrated, that this isn't working, mostly because it isn't giving me any error logs, or output at all. I submit the job, and as far as I can tell nothing happens. Is there some status, or debugging level that I can set to get a useful information about why this isn't working? What can I do to make this work? I was originally running Bacula 5.0.2 on Debian Squeeze, out of frustration, I upgraded to the 5.2.6 in the backports repository, hoping that a new version might give me better results.

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• SQL Server 2008 - Error starting service - model.mdf not found?!

  - by alex

  my SQL server 2008 was running fine. About an hour ago, it suddenly stopped - the MSSQLSERVER service had stopped I right clicked, clicked start, and it said the service had started, and stopped I looked in the event log and saw these two errors: 17207 : udopen: Operating system error 3(error not found) during the creation/opening of physical device C:\Program Files\Microsoft SQL Server\MSSQL\data\model.mdf. 17204 : FCB::Open failed: Could not open device C:\Program Files\Microsoft SQL Server\MSSQL\data\model.mdf for virtual device number (VDN) 1. The model.mdf db has NEVER been in that location - i specified drive F: to use for data / log during install. I checked the SQL Configuration Manager, to try and set startup params, but SQL Server is not listed as one of the services..... EDIT: I've now moved the db to where it was looking for: C:\Program Files\Microsoft SQL Server\MSSQL\data\ directory. Now if I start the service, it still does not work - i get this error message in the log: Could not find row in sysindexes for database ID 3, object ID 1, index ID 1. Run DBCC CHECKTABLE on sysindexes. Interestingly, i checked the error log - around the time users reported problems, there is this: 2010-01-08 17:11:26.44 spid51 Configuration option 'show advanced options' changed from 0 to 1. Run the RECONFIGURE statement to install. 2010-01-08 17:11:26.44 spid51 FILESTREAM: effective level = 0, configured level = 0, file system access share name = 'MSSQLSERVER'. 2010-01-08 17:11:26.44 spid51 Configuration option 'Agent XPs' changed from 1 to 0. Run the RECONFIGURE statement to install. 2010-01-08 17:11:26.44 spid51 FILESTREAM: effective level = 0, configured level = 0, file system access share name = 'MSSQLSERVER'. 2010-01-08 17:11:26.44 spid51 Configuration option 'show advanced options' changed from 1 to 0. Run the RECONFIGURE statement to install. 2010-01-08 17:11:26.44 spid51 FILESTREAM: effective level = 0, configured level = 0, file system access share name = 'MSSQLSERVER'. 2010-01-08 17:11:44.89 spid10s Service Broker manager has shut down. 2010-01-08 17:11:47.83 spid7s SQL Server is terminating in response to a 'stop' request from Service Control Manager. This is an informational message only. No user action is required. 2010-01-08 17:11:47.83 spid7s SQL Trace was stopped due to server shutdown. Trace ID = '1'. This is an informational message only; no user action is required.

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• SQL Server Read Locking behavior

  - by Charles Bretana

  When SQL Server Books online says that "Shared (S) locks on a resource are released as soon as the read operation completes, unless the transaction isolation level is set to repeatable read or higher, or a locking hint is used to retain the shared (S) locks for the duration of the transaction." Assuming we're talking about a row-level lock, with no explicit transaction, at default isolation level (Read Committed), what does "read operation" refer to? The reading of a single row of data? The reading of a single 8k IO Page ? or until the the complete Select statement in which the lock was created has finished executing, no matter how many other rows are involved? NOTE: The reason I need to know this is we have a several second read-only select statement generated by a data layer web service, which creates page-level shared read locks, generating a deadlock due to conflicting with row-level exclusive update locks from a replication prcoess that keeps the server updated. The select statement is fairly large, with many sub-selects, and one DBA is proposing that we rewrite it to break it up into multiple smaller statements (shorter running pieces), "to cut down on how long the locks are held". As this assumes that the shared read locks are held till the complete select statement has finished, if that is wrong (if locks are released when the row, or the page is read) then that approach would have no effect whatsoever....

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• Logfiles filling with iptables logging

  - by Peter I

  OS: Debian 6 Server Version I have different logfiles which are filling up: user@server:/var/log$ ls -lahS | head total 427G -rw-r--r-- 1 root root 267G Nov 2 17:29 bandwidth -rw-r----- 1 root adm 44G Nov 2 17:29 kern.log -rw-r----- 1 root adm 27G Nov 2 17:29 debug -rw-r----- 1 root adm 23G Oct 27 06:33 kern.log.1 -rw-r----- 1 root adm 17G Nov 2 17:29 messages -rw-r----- 1 root adm 14G Oct 27 06:33 debug.1 -rw-r----- 1 root adm 12G Nov 2 17:29 syslog -rw-r----- 1 root adm 12G Nov 1 06:26 syslog.1 -rw-r----- 1 root adm 9.0G Oct 27 06:33 messages.1 So I looked up the file /etc/iptables.up.rules which had those lines in it: -A FORWARD -o eth0 -j LOG --log-level 7 --log-prefix BANDWIDTH_OUT: -A FORWARD -i eth0 -j LOG --log-level 7 --log-prefix BANDWIDTH_IN: -A OUTPUT -o eth0 -j LOG --log-level 7 --log-prefix BANDWIDTH_OUT: -A INPUT -i eth0 -j LOG --log-level 7 --log-prefix BANDWIDTH_IN: So deleting those lines will solve my problem. But how would I edit those lines without losing their functionality?

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• How cpu writes data to dynamic RAM

  - by Krit

  Hello, I would like to know what kind of electrical signals does a cpu send to a dynamic RAM when it wants to write one bit (a 1 or 0). Is it simply that cpu sends just a single electric pulse, and if that electric pulse's voltage is higher than a certain level, it charges the capacitor to a voltage level that is "1" and if it is at a lower voltage band, it charges capacitor to level that it is "0"?

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• ZFS, dedupe and PST files

  - by Unreason

  I am interested to know what would be expected maximum dedupe ratio for a set of PST files. I have ~40G of pst files from ~15 usres with high level of duplication of attachments. I am running tests to see if I can have significant space savings if I store the data on ZFS with dedupe. For this purpose I have installed a test setup of Nexenta, but was wondering if someone here had already done this and what level of deduplication I might expect (or in another words how sensitive are pst files to block alignment and what are the parameters that can influence the ratio?). Initial test show very low dedupe ratio and I did find explanation that block level dedupe would not be efficient here and that byte level dedupe would be much better (and that it should be performed by application that is aware of internal organization), so I am just double checking here if someone have some more input. Otherwise I will probably be converting PST files to IMAP.

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• Minimize HTML, CSS and JS files

  - by karmic

  How do you automatically pack/minimize the HTML, CSS and JS files served on a webpage. More specifically, I wish to have this for a wordpress website. Should it be done at the webserver level (lighttpd), at the application level (wordpress), at the PHP level, or somewhere else?

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• FFMPEG, FLAC. How do i encode with highest compression?

  - by acidzombie24

  With FFMPEG how do i encode a lossless codec (ATM i am testing with another flac) to a flac file with the highest compression level. With MediaMonkey i was able to compress to level 8 and i recompressed with ffmpeg and it matched the output of a level 6 compress. Even with -aq 8. How do i set it to the highest compression?

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• What are the most common dangerous domains that I should block?

  - by Dalia

  I am trying to configure my wireless router to block domains that are potentially dangerous to privacy, security, and bandwidth-hogs. Is there a list of domains that I can block at the router level? On a machine level, I have set the hosts file from www.mvps.org and that works on my machine. However, I want to implement something at the router level too - so that all computers in my household are somewhat protected.

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• game state singleton cocos2d, initWithEncoder always returns null

  - by taber

  Hi, I'm trying to write a basic test "game state" singleton in cocos2d, but for some reason upon loading the app, initWithCoder is never called. Any help would be much appreciated, thanks. Here's my singleton GameState.h: #import "cocos2d.h" @interface GameState : NSObject <NSCoding> { NSInteger level, score; Boolean seenInstructions; } @property (readwrite) NSInteger level; @property (readwrite) NSInteger score; @property (readwrite) Boolean seenInstructions; +(GameState *) sharedState; +(void) loadState; +(void) saveState; @end ... and GameState.m: #import "GameState.h" #import "Constants.h" @implementation GameState static GameState *sharedState = nil; @synthesize level, score, seenInstructions; -(void)dealloc { [super dealloc]; } -(id)init { if(!(self = [super init])) return nil; level = 1; score = 0; seenInstructions = NO; return self; } +(void)loadState { @synchronized([GameState class]) { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *saveFile = [documentsDirectory stringByAppendingPathComponent:kSaveFileName]; Boolean saveFileExists = [[NSFileManager defaultManager] fileExistsAtPath:saveFile]; if(!sharedState) { sharedState = [GameState sharedState]; } if(saveFileExists == YES) { [sharedState release]; sharedState = [[NSKeyedUnarchiver unarchiveObjectWithFile:saveFile] retain]; } // at this point, sharedState is null, saveFileExists is 1 if(sharedState == nil) { // this always occurs CCLOG(@"Couldn't load game state, so initialized with defaults"); sharedState = [self sharedState]; } } } +(void)saveState { NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *saveFile = [documentsDirectory stringByAppendingPathComponent:kSaveFileName]; [NSKeyedArchiver archiveRootObject:[GameState sharedState] toFile:saveFile]; } +(GameState *)sharedState { @synchronized([GameState class]) { if(!sharedState) { [[GameState alloc] init]; } return sharedState; } return nil; } +(id)alloc { @synchronized([GameState class]) { NSAssert(sharedState == nil, @"Attempted to allocate a second instance of a singleton."); sharedState = [super alloc]; return sharedState; } return nil; } +(id)allocWithZone:(NSZone *)zone { @synchronized([GameState class]) { if(!sharedState) { sharedState = [super allocWithZone:zone]; return sharedState; } } return nil; } ... -(void)encodeWithCoder:(NSCoder *)coder { [coder encodeInt:level forKey:@"level"]; [coder encodeInt:score forKey:@"score"]; [coder encodeBool:seenInstructions forKey:@"seenInstructions"]; } -(id)initWithCoder:(NSCoder *)coder { CCLOG(@"initWithCoder called"); self = [super init]; if(self != nil) { CCLOG(@"initWithCoder self exists"); level = [coder decodeIntForKey:@"level"]; score = [coder decodeIntForKey:@"score"]; seenInstructions = [coder decodeBoolForKey:@"seenInstructions"]; } return self; } @end ... I'm saving the state on app exit, like this: - (void)applicationWillTerminate:(UIApplication *)application { [GameState saveState]; [[CCDirector sharedDirector] end]; } ... and loading the state when the app finishes loading, like this: - (BOOL) application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { ... [GameState loadState]; ... } I've tried moving around where I call loadState too, for example in my main CCScene, but that didn't seem to work either. Thanks again in advance.

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• Difference between SQL 2005 and SQL 2008 for inserting multiple rows with XML

  - by Sam Dahan

  I am using the following SQL code for inserting multiple rows of data in a table. The data is passed to the stored procedure using an XML variable : INSERT INTO MyTable SELECT SampleTime = T.Item.value('SampleTime[1]', 'datetime'), Volume1 = T.Item.value('Volume1[1]', 'float'), Volume2 = T.Item.value('Volume2[1]', 'float') FROM @xml.nodes('//Root/MyRecord') T(item) I have a whole bunch of unit tests to verify that I am inserting the right information, the right number of records, etc.. when I call the stored procedure. All fine and dandy - that is, until we began to monkey around with the compatibility level of the database. The code above worked beautifully as long as we kept the compatibility level of the DB at 90 (SQL 2005). When we set the compatibility level at 100 (SQL 2008), the unit tests failed, because the stored procedure using the code above times out. The unit tests are dropping the database, re-creating it from scripts, and running the tests on the brand new DB, so it's not - I think - a question of the 'old compatibility level' sticking around. Using the SQL Management studio, I made up a quick test SQL script. Using the same XML chunk, I alter the DB compat level , truncate the table, then use the code above to insert 650 rows. When the level is 90 (SQL 2005), it runs in milliseconds. When the level is 100 (SQL 2008) it sometimes takes over a minute, sometimes runs in milliseconds. I'd appreciate any insight anyone might have into that. EDIT The script takes over a minute to run with my actual data, which has more rows than I show here, is a real table, and has an index. With the following example code, the difference goes between milliseconds and around 5 seconds. --use [master] --ALTER DATABASE MyDB SET compatibility_level =100 use [MyDB] declare @xml xml set @xml = '<?xml version="1.0"?> <Root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Record> <SampleTime>2009-01-24T00:00:00</SampleTime> <Volume1>0</Volume1> <Volume2>0</Volume2> </Record> ..... 653 records, sample time spaced out 4 hours ........ </Root>' DECLARE @myTable TABLE( ID int IDENTITY(1,1) NOT NULL, [SampleTime] [datetime] NOT NULL, [Volume1] [float] NULL, [Volume2] [float] NULL) INSERT INTO @myTable select T.Item.value('SampleTime[1]', 'datetime') as SampleTime, Volume1 = T.Item.value('Volume1[1]', 'float'), Volume2 = T.Item.value('Volume2[1]', 'float') FROM @xml.nodes('//Root/Record') T(item) I uncomment the 2 lines at the top, select them and run just that (the ALTER DATABASE statement), then comment the 2 lines, deselect any text and run the whole thing. When I change from 90 to 100, it runs all the time in 5 seconds (I change the level once, but I run the series several times to see if I have consistent results). When I change from 100 to 90, it runs in milliseconds all the time. Just so you can play with it too. I am using SQL Server 2008 R2 standard edition.

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• Good SQL error handling in Strored Procedure

  - by developerit

  When writing SQL procedures, it is really important to handle errors cautiously. Having that in mind will probably save your efforts, time and money. I have been working with MS-SQL 2000 and MS-SQL 2005 (I have not got the opportunity to work with MS-SQL 2008 yet) for many years now and I want to share with you how I handle errors in T-SQL Stored Procedure. This code has been working for many years now without a hitch. N.B.: As antoher "best pratice", I suggest using only ONE level of TRY … CATCH and only ONE level of TRANSACTION encapsulation, as doing otherwise may not be 100% sure. BEGIN TRANSACTION; BEGIN TRY -- Code in transaction go here COMMIT TRANSACTION; END TRY BEGIN CATCH -- Rollback on error ROLLBACK TRANSACTION; -- Raise the error with the appropriate message and error severity DECLARE @ErrMsg nvarchar(4000), @ErrSeverity int; SELECT @ErrMsg = ERROR_MESSAGE(), @ErrSeverity = ERROR_SEVERITY(); RAISERROR(@ErrMsg, @ErrSeverity, 1); END CATCH; In conclusion, I will just mention that I have been using this code with .NET 2.0 and .NET 3.5 and it works like a charm. The .NET TDS parser throws back a SQLException which is ideal to work with.

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• When runs a product out of support?

  That is a question I get regularly from customers. Microsoft has a great site where you can find that information. Unfortunately this site is not easy to find, and a lot of people are not aware of this site. A good reason to promote it a little. So if you ever get a question on this topic, go to http://support.microsoft.com/lifecycle/search/Default.aspx. At that site, you can find also the details of the policy Microsoft Support Lifecycle Policy The Microsoft Support Lifecycle policy took effect in October 2002, and applies to most products currently available through retail purchase or volume licensing and most future release products. Through the policy, Microsoft will offer a minimum of: 10 years of support (5 years Mainstream Support and 5 years Extended Support) at the supported service pack level for Business and Developer products 5 years Mainstream Support at the supported service pack level for Consumer/Hardware/Multimedia products 3 years of Mainstream Support for products that are annually released (for example, Money, Encarta, Picture It!, and Streets & Trips) Phases of the Support Lifecycle Mainstream Support Mainstream Support is the first phase of the product support lifecycle. At the supported service pack level, Mainstream Support includes: Incident support (no-charge incident support, paid incident support, support charged on an hourly basis, support for warranty claims) Security update support The ability to request non-security hotfixes Please note: Enrollment in a maintenance program may be required to receive these benefits for certain products Extended Support The Extended Support phase follows Mainstream Support for Business and Developer products. At the supported service pack level, Extended Support includes: Paid support Security update support at no additional cost Non-security related hotfix support requires a separate Extended Hotfix Support Agreement to be purchased (per-fix fees also apply) Please note: Microsoft will not accept requests for warranty support, design changes, or new features during the Extended Support phase Extended Support is not available for Consumer, Hardware, or Multimedia products Enrollment in a maintenance program may be required to receive these benefits for certain products Self-Help Online Support Self-Help Online Support is available throughout a product's lifecycle and for a minimum of 12 months after the product reaches the end of its support. Microsoft online Knowledge Base articles, FAQs, troubleshooting tools, and other resources, are provided to help customers resolve common issues. Please note: Enrollment in a maintenance program may be required to receive these benefits for certain products (source: http://support.microsoft.com/lifecycle/#tab1)

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• [GEEK SCHOOL] Network Security 2: Preventing Disaster with User Account Control

  - by Ciprian Rusen

  In this second lesson in our How-To Geek School about securing the Windows devices in your network, we will talk about User Account Control (UAC). Users encounter this feature each time they need to install desktop applications in Windows, when some applications need administrator permissions in order to work and when they have to change different system settings and files. UAC was introduced in Windows Vista as part of Microsoft’s “Trustworthy Computing” initiative. Basically, UAC is meant to act as a wedge between you and installing applications or making system changes. When you attempt to do either of these actions, UAC will pop up and interrupt you. You may either have to confirm you know what you’re doing, or even enter an administrator password if you don’t have those rights. Some users find UAC annoying and choose to disable it but this very important security feature of Windows (and we strongly caution against doing that). That’s why in this lesson, we will carefully explain what UAC is and everything it does. As you will see, this feature has an important role in keeping Windows safe from all kinds of security problems. In this lesson you will learn which activities may trigger a UAC prompt asking for permissions and how UAC can be set so that it strikes the best balance between usability and security. You will also learn what kind of information you can find in each UAC prompt. Last but not least, you will learn why you should never turn off this feature of Windows. By the time we’re done today, we think you will have a newly found appreciation for UAC, and will be able to find a happy medium between turning it off completely and letting it annoy you to distraction. What is UAC and How Does it Work? UAC or User Account Control is a security feature that helps prevent unauthorized system changes to your Windows computer or device. These changes can be made by users, applications, and sadly, malware (which is the biggest reason why UAC exists in the first place). When an important system change is initiated, Windows displays a UAC prompt asking for your permission to make the change. If you don’t give your approval, the change is not made. In Windows, you will encounter UAC prompts mostly when working with desktop applications that require administrative permissions. For example, in order to install an application, the installer (generally a setup.exe file) asks Windows for administrative permissions. UAC initiates an elevation prompt like the one shown earlier asking you whether it is okay to elevate permissions or not. If you say “Yes”, the installer starts as administrator and it is able to make the necessary system changes in order to install the application correctly. When the installer is closed, its administrator privileges are gone. If you run it again, the UAC prompt is shown again because your previous approval is not remembered. If you say “No”, the installer is not allowed to run and no system changes are made. If a system change is initiated from a user account that is not an administrator, e.g. the Guest account, the UAC prompt will also ask for the administrator password in order to give the necessary permissions. Without this password, the change won’t be made. Which Activities Trigger a UAC Prompt? There are many types of activities that may trigger a UAC prompt: Running a desktop application as an administrator Making changes to settings and files in the Windows and Program Files folders Installing or removing drivers and desktop applications Installing ActiveX controls Changing settings to Windows features like the Windows Firewall, UAC, Windows Update, Windows Defender, and others Adding, modifying, or removing user accounts Configuring Parental Controls in Windows 7 or Family Safety in Windows 8.x Running the Task Scheduler Restoring backed-up system files Viewing or changing the folders and files of another user account Changing the system date and time You will encounter UAC prompts during some or all of these activities, depending on how UAC is set on your Windows device. If this security feature is turned off, any user account or desktop application can make any of these changes without a prompt asking for permissions. In this scenario, the different forms of malware existing on the Internet will also have a higher chance of infecting and taking control of your system. In Windows 8.x operating systems you will never see a UAC prompt when working with apps from the Windows Store. That’s because these apps, by design, are not allowed to modify any system settings or files. You will encounter UAC prompts only when working with desktop programs. What You Can Learn from a UAC Prompt? When you see a UAC prompt on the screen, take time to read the information displayed so that you get a better understanding of what is going on. Each prompt first tells you the name of the program that wants to make system changes to your device, then you can see the verified publisher of that program. Dodgy software tends not to display this information and instead of a real company name, you will see an entry that says “Unknown”. If you have downloaded that program from a less than trustworthy source, then it might be better to select “No” in the UAC prompt. The prompt also shares the origin of the file that’s trying to make these changes. In most cases the file origin is “Hard drive on this computer”. You can learn more by pressing “Show details”. You will see an additional entry named “Program location” where you can see the physical location on your hard drive, for the file that’s trying to perform system changes. Make your choice based on the trust you have in the program you are trying to run and its publisher. If a less-known file from a suspicious location is requesting a UAC prompt, then you should seriously consider pressing “No”. What’s Different About Each UAC Level? Windows 7 and Windows 8.x have four UAC levels: Always notify – when this level is used, you are notified before desktop applications make changes that require administrator permissions or before you or another user account changes Windows settings like the ones mentioned earlier. When the UAC prompt is shown, the desktop is dimmed and you must choose “Yes” or “No” before you can do anything else. This is the most secure and also the most annoying way to set UAC because it triggers the most UAC prompts. Notify me only when programs/apps try to make changes to my computer (default) – Windows uses this as the default for UAC. When this level is used, you are notified before desktop applications make changes that require administrator permissions. If you are making system changes, UAC doesn’t show any prompts and it automatically gives you the necessary permissions for making the changes you desire. When a UAC prompt is shown, the desktop is dimmed and you must choose “Yes” or “No” before you can do anything else. This level is slightly less secure than the previous one because malicious programs can be created for simulating the keystrokes or mouse moves of a user and change system settings for you. If you have a good security solution in place, this scenario should never occur. Notify me only when programs/apps try to make changes to my computer (do not dim my desktop) – this level is different from the previous in in the fact that, when the UAC prompt is shown, the desktop is not dimmed. This decreases the security of your system because different kinds of desktop applications (including malware) might be able to interfere with the UAC prompt and approve changes that you might not want to be performed. Never notify – this level is the equivalent of turning off UAC. When using it, you have no protection against unauthorized system changes. Any desktop application and any user account can make system changes without your permission. How to Configure UAC If you would like to change the UAC level used by Windows, open the Control Panel, then go to “System and Security” and select “Action Center”. On the column on the left you will see an entry that says “Change User Account Control settings”. The “User Account Control Settings” window is now opened. Change the position of the UAC slider to the level you want applied then press “OK”. Depending on how UAC was initially set, you may receive a UAC prompt requiring you to confirm this change. Why You Should Never Turn Off UAC If you want to keep the security of your system at decent levels, you should never turn off UAC. When you disable it, everything and everyone can make system changes without your consent. This makes it easier for all kinds of malware to infect and take control of your system. It doesn’t matter whether you have a security suite or antivirus installed or third-party antivirus, basic common-sense measures like having UAC turned on make a big difference in keeping your devices safe from harm. We have noticed that some users disable UAC prior to setting up their Windows devices and installing third-party software on them. They keep it disabled while installing all the software they will use and enable it when done installing everything, so that they don’t have to deal with so many UAC prompts. Unfortunately this causes problems with some desktop applications. They may fail to work after you enable UAC. This happens because, when UAC is disabled, the virtualization techniques UAC uses for your applications are inactive. This means that certain user settings and files are installed in a different place and when you turn on UAC, applications stop working because they should be placed elsewhere. Therefore, whatever you do, do not turn off UAC completely! Coming up next … In the next lesson you will learn about Windows Defender, what this tool can do in Windows 7 and Windows 8.x, what’s different about it in these operating systems and how it can be used to increase the security of your system.

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