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  • Using Resources the Right Way

    - by BuckWoody
    It’s an interesting time in computing technology. At one point there was a dearth of information available for solving a given problem, or educating ourselves on broader topics so that we can solve problems in the future. With dozens, perhaps hundreds or thousands of web sites and content available (for free, in many cases) from vendors, peers, even colleges and universities, it seems like there is actually too much information. Who has the time to absorb all this information and training? Even if you had the inclination, where to start? In fact, it seems so overwhelming that I often hear people saying that they can’t find the training they need, or that vendor X or Y “doesn’t help their users”. On questioning these folks, however, I often find that they – and sometimes I - haven’t put in the effort to learn what resources we have. That’s where blogs, like this one, can help. If you follow a blog, either by checking it often or perhaps subscribing to the Really Simple Syndication (RSS) feed, you’ll be able to spread out the search or create a mental filter for the information you need. But it’s not enough just read a blog or a web page. The creators need real feedback – what doesn’t work, and what does. Yes, you’re allowed to tell a vendor or writer “This helped me because…” so that you reinforce the positives. To be sure, bring up what doesn’t work as well –  that’s fine. But be specific, and be constructive. You’d be surprised at how much it matters. I know for a fact at Microsoft we listen – there is a real live person that reads your comments. I’m sure this is true of other vendors, and I also know that most blog authors – yours truly most especially – wants to know what you think.   In this blog entry I’d to call your attention to three resources you have at your disposal, and how you can use them to help. I’ll try to bring up things like this from time to time that I find useful, and cover in them in more depth like this. Think of this as a synopsis of a longer set of resources that you can use to filter whether you want to research further, bookmark, or forward on to a circle of friends where you think it might help them.   Data Driven Design Concepts http://msdn.microsoft.com/en-us/library/windowsazure/jj156154 I’ll start with a great site that walks you through the process of designing a solution from a data-first perspective. As you know, I believe all computing is merely re-arranging data. If you follow that logic as well, you’ll realize that whenever you create a solution, you should start at the data-end of the application. This resource helps you do that. Even if you don’t use the specific technologies the instructions use, the concepts hold for almost any other technology that deals with data. This should be a definite bookmark for a developer, DBA, or Data Architect. When I mentioned my admiration for this resource here at Microsoft, the team that created it contacted me and asked if I’d share an e-mail address to my readers so that you can comment on it. You’re guaranteed to be heard – you can suggest changes, talk about how useful – or not – it is, and so on. Here’s that address:  [email protected]   End-to-End Example of a complete Hybrid Application – with Live Demo https://azurestocktrader.cloudapp.net/Default.aspx I learn by example. I also like having ready-made, live, functional demos that show the completed solution at work. If you’ve ever wanted to learn how a complex, complete, hybrid application that bridges on-premises systems with cloud-based databases, code, functions and more, this is it. It’s a stock-trading simulator, and you can get everything from the design to the code itself, or you can just play with the application. It’s running on Windows Azure, the actual production servers we use for everything else. Using a Cloud-Based Service https://azureconfigweb.cloudapp.net/Default.aspx Along with that stock-trading application, you have a full demonstration and usable code sample of a web-based service available. If you’re a developer, this is a style of code you need to understand for everything from iPhone development to a full Service-Oriented Architecture (SOA) environment. So check out these resources. I’ll post more from time to time as I run across them. Hopefully they’ll be as useful to you as they are to me. Oh, and if you have a comment on any of the resources, let them know. And if you have any comments about these or any of my entries, feel free to post away. To quote a famous TV Show: “Hello Seattle – I’m listening…”

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  • ANTS CLR and Memory Profiler In Depth Review (Part 2 of 2 &ndash; Memory Profiler)

    - by ToStringTheory
    One of the things that people might not know about me, is my obsession to make my code as efficient as possible. Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind… In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve. One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well. In this review, I am going to cover some of the features of the ANTS memory profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program. I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction – Part 2 In my last post, I reviewed the feature packed Red Gate ANTS Performance Profiler.  Separate from the Red Gate Performance Profiler is the Red Gate ANTS Memory Profiler – a simple, easy to use utility for checking how your application is handling memory management…  A tool that I wish I had had many times in the past.  This post will be focusing on the ANTS Memory Profiler and its tool set. The memory profiler has a large assortment of features just like the Performance Profiler, with the new session looking nearly exactly alike: ANTS Memory Profiler Memory profiling is not something that I have to do very often…  In the past, the few cases I’ve had to find a memory leak in an application I have usually just had to trace the code of the operations being performed to look for oddities…  Sadly, I have come across more undisposed/non-using’ed IDisposable objects, usually from ADO.Net than I would like to ever see.  Support is not fun, however using ANTS Memory Profiler makes this task easier.  For this round of testing, I am going to use the same code from my previous example, using the WPF application. This time, I will choose the ‘Profile Memory’ option from the ANTS menu in Visual Studio, which launches the solution in its currently configured state/start-up project, and then launches the ANTS Memory Profiler to help.  It prepopulates all of the fields with the current project information, and all I have to do is select the ‘Start Profiling’ option. When the window comes up, it is actually quite barren, just giving ideas on how to work the profiler.  You start by getting to the point in your application that you want to profile, and then taking a ‘Memory Snapshot’.  This performs a full garbage collection, and snapshots the managed heap.  Using the same WPF app as before, I will go ahead and take a snapshot now. As you can see, ANTS is already giving me lots of information regarding the snapshot, however this is just a snapshot.  The whole point of the profiler is to perform an action, usually one where a memory problem is being noticed, and then take another snapshot and perform a diff between them to see what has changed.  I am going to go ahead and generate 5000 primes, and then take another snapshot: As you can see, ANTS is already giving me a lot of new information about this snapshot compared to the last.  Information such as difference in memory usage, fragmentation, class usage, etc…  If you take more snapshots, you can use the dropdown at the top to set your actual comparison snapshots. If you beneath the timeline, you will see a breadcrumb trail showing how best to approach profiling memory using ANTS.  When you first do the comparison, you start on the Summary screen.  You can either use the charts at the bottom, or switch to the class list screen to get to the next step.  Here is the class list screen: As you can see, it lists information about all of the instances between the snapshots, as well as at the bottom giving you a way to filter by telling ANTS what your problem is.  I am going to go ahead and select the Int16[] to look at the Instance Categorizer Using the instance categorizer, you can travel backwards to see where all of the instances are coming from.  It may be hard to see in this image, but hopefully the lightbox (click on it) will help: I can see that all of these instances are rooted to the application through the UI TextBlock control.  This image will probably be even harder to see, however using the ‘Instance Retention Graph’, you can trace an objects memory inheritance up the chain to see its roots as well.  This is a simple example, as this is simply a known element.  Usually you would be profiling an actual problem, and comparing those differences.  I know in the past, I have spotted a problem where a new context was created per page load, and it was rooted into the application through an event.  As the application began to grow, performance and reliability problems started to emerge.  A tool like this would have been a great way to identify the problem quickly. Overview Overall, I think that the Red Gate ANTS Memory Profiler is a great utility for debugging those pesky leaks.  3 Biggest Pros: Easy to use interface with lots of options for configuring profiling session Intuitive and helpful interface for drilling down from summary, to instance, to root graphs ANTS provides an API for controlling the profiler. Not many options, but still helpful. 2 Biggest Cons: Inability to automatically snapshot the memory by interval Lack of complete integration with Visual Studio via an extension panel Ratings Ease of Use (9/10) – I really do believe that they have brought simplicity to the once difficult task of memory profiling.  I especially liked how it stepped you further into the drilldown by directing you towards the best options. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do.  Features (7/10) – A really great set of features all around in the application, however, I would like to see some ability for automatically triggering snapshots based on intervals or framework level items such as events. Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good.  their people are friendly, helpful, and happy! UI / UX (9/10) – The interface is very easy to get around, and all of the options are easy to find.  With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (9/10) – Overall, I am happy with the Memory Profiler and its features, as well as with the service I received when working with the Red Gate personnel.  Thank you for reading up to here, or skipping ahead – I told you it would be shorter!  Please, if you do try the product, drop me a message and let me know what you think!  I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

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  • Cloud to On-Premise Connectivity Patterns

    - by Rajesh Raheja
    Do you have a requirement to convert an Opportunity in Salesforce.com to an Order/Quote in Oracle E-Business Suite? Or maybe you want the creation of an Oracle RightNow Incident to trigger an on-premise Oracle E-Business Suite Service Request creation for RMA and Field Scheduling? If so, read on. In a previous blog post, I discussed integrating TO cloud applications, however the use cases above are the reverse i.e. receiving data FROM cloud applications (SaaS) TO on-premise applications/databases that sit behind a firewall. Oracle SOA Suite is assumed to be on-premise with with Oracle Service Bus as the mediation and virtualization layer. The main considerations for the patterns are are security i.e. shielding enterprise resources; and scalability i.e. minimizing firewall latency. Let me use an analogy to help visualize the patterns: the on-premise system is your home - with your most valuable possessions - and the SaaS app is your favorite on-line store which regularly ships (inbound calls) various types of parcels/items (message types/service operations). You need the items at home (on-premise) but want to safe guard against misguided elements of society (internet threats) who may masquerade as postal workers and vandalize property (denial of service?). Let's look at the patterns. Pattern: Pull from Cloud The on-premise system polls from the SaaS apps and picks up the message instead of having it delivered. This may be done using Oracle RightNow Object Query Language or SOAP APIs. This is particularly suited for certain integration approaches wherein messages are trickling in, can be centralized and batched e.g. retrieving event notifications on an hourly schedule from the Oracle Messaging Service. To compare this pattern with the home analogy, you are avoiding any deliveries to your home and instead go to the post office/UPS/Fedex store to pick up your parcel. Every time. Pros: On-premise assets not exposed to the Internet, firewall issues avoided by only initiating outbound connections Cons: Polling mechanisms may affect performance, may not satisfy near real-time requirements Pattern: Open Firewall Ports The on-premise system exposes the web services that needs to be invoked by the cloud application. This requires opening up firewall ports, routing calls to the appropriate internal services behind the firewall. Fusion Applications uses this pattern, and auto-provisions the services on the various virtual hosts to secure the topology. This works well for service integration, but may not suffice for large volume data integration. Using the home analogy, you have now decided to receive parcels instead of going to the post office every time. A door mail slot cut out allows the postman can drop small parcels, but there is still concern about cutting new holes for larger packages. Pros: optimal pattern for near real-time needs, simpler administration once the service is provisioned Cons: Needs firewall ports to be opened up for new services, may not suffice for batch integration requiring direct database access Pattern: Virtual Private Networking The on-premise network is "extended" to the cloud (or an intermediary on-demand / managed service offering) using Virtual Private Networking (VPN) so that messages are delivered to the on-premise system in a trusted channel. Using the home analogy, you entrust a set of keys with a neighbor or property manager who receives the packages, and then drops it inside your home. Pros: Individual firewall ports don't need to be opened, more suited for high scalability needs, can support large volume data integration, easier management of one connection vs a multitude of open ports Cons: VPN setup, specific hardware support, requires cloud provider to support virtual private computing Pattern: Reverse Proxy / API Gateway The on-premise system uses a reverse proxy "API gateway" software on the DMZ to receive messages. The reverse proxy can be implemented using various mechanisms e.g. Oracle API Gateway provides firewall and proxy services along with comprehensive security, auditing, throttling benefits. If a firewall already exists, then Oracle Service Bus or Oracle HTTP Server virtual hosts can provide reverse proxy implementations on the DMZ. Custom built implementations are also possible if specific functionality (such as message store-n-forward) is needed. In the home analogy, this pattern sits in between cutting mail slots and handing over keys. Instead, you install (and maintain) a mailbox in your home premises outside your door. The post office delivers the parcels in your mailbox, from where you can securely retrieve it. Pros: Very secure, very flexible Cons: Introduces a new software component, needs DMZ deployment and management Pattern: On-Premise Agent (Tunneling) A light weight "agent" software sits behind the firewall and initiates the communication with the cloud, thereby avoiding firewall issues. It then maintains a bi-directional connection either with pull or push based approaches using (or abusing, depending on your viewpoint) the HTTP protocol. Programming protocols such as Comet, WebSockets, HTTP CONNECT, HTTP SSH Tunneling etc. are possible implementation options. In the home analogy, a resident receives the parcel from the postal worker by opening the door, however you still take precautions with chain locks and package inspections. Pros: Light weight software, IT doesn't need to setup anything Cons: May bypass critical firewall checks e.g. virus scans, separate software download, proliferation of non-IT managed software Conclusion The patterns above are some of the most commonly encountered ones for cloud to on-premise integration. Selecting the right pattern for your project involves looking at your scalability needs, security restrictions, sync vs asynchronous implementation, near real-time vs batch expectations, cloud provider capabilities, budget, and more. In some cases, the basic "Pull from Cloud" may be acceptable, whereas in others, an extensive VPN topology may be well justified. For more details on the Oracle cloud integration strategy, download this white paper.

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  • Cloud to On-Premise Connectivity Patterns

    - by Rajesh Raheja
    Do you have a requirement to convert an Opportunity in Salesforce.com to an Order/Quote in Oracle E-Business Suite? Or maybe you want the creation of an Oracle RightNow Incident to trigger an on-premise Oracle E-Business Suite Service Request creation for RMA and Field Scheduling? If so, read on. In a previous blog post, I discussed integrating TO cloud applications, however the use cases above are the reverse i.e. receiving data FROM cloud applications (SaaS) TO on-premise applications/databases that sit behind a firewall. Oracle SOA Suite is assumed to be on-premise with with Oracle Service Bus as the mediation and virtualization layer. The main considerations for the patterns are are security i.e. shielding enterprise resources; and scalability i.e. minimizing firewall latency. Let me use an analogy to help visualize the patterns: the on-premise system is your home - with your most valuable possessions - and the SaaS app is your favorite on-line store which regularly ships (inbound calls) various types of parcels/items (message types/service operations). You need the items at home (on-premise) but want to safe guard against misguided elements of society (internet threats) who may masquerade as postal workers and vandalize property (denial of service?). Let's look at the patterns. Pattern: Pull from Cloud The on-premise system polls from the SaaS apps and picks up the message instead of having it delivered. This may be done using Oracle RightNow Object Query Language or SOAP APIs. This is particularly suited for certain integration approaches wherein messages are trickling in, can be centralized and batched e.g. retrieving event notifications on an hourly schedule from the Oracle Messaging Service. To compare this pattern with the home analogy, you are avoiding any deliveries to your home and instead go to the post office/UPS/Fedex store to pick up your parcel. Every time. Pros: On-premise assets not exposed to the Internet, firewall issues avoided by only initiating outbound connections Cons: Polling mechanisms may affect performance, may not satisfy near real-time requirements Pattern: Open Firewall Ports The on-premise system exposes the web services that needs to be invoked by the cloud application. This requires opening up firewall ports, routing calls to the appropriate internal services behind the firewall. Fusion Applications uses this pattern, and auto-provisions the services on the various virtual hosts to secure the topology. This works well for service integration, but may not suffice for large volume data integration. Using the home analogy, you have now decided to receive parcels instead of going to the post office every time. A door mail slot cut out allows the postman can drop small parcels, but there is still concern about cutting new holes for larger packages. Pros: optimal pattern for near real-time needs, simpler administration once the service is provisioned Cons: Needs firewall ports to be opened up for new services, may not suffice for batch integration requiring direct database access Pattern: Virtual Private Networking The on-premise network is "extended" to the cloud (or an intermediary on-demand / managed service offering) using Virtual Private Networking (VPN) so that messages are delivered to the on-premise system in a trusted channel. Using the home analogy, you entrust a set of keys with a neighbor or property manager who receives the packages, and then drops it inside your home. Pros: Individual firewall ports don't need to be opened, more suited for high scalability needs, can support large volume data integration, easier management of one connection vs a multitude of open ports Cons: VPN setup, specific hardware support, requires cloud provider to support virtual private computing Pattern: Reverse Proxy / API Gateway The on-premise system uses a reverse proxy "API gateway" software on the DMZ to receive messages. The reverse proxy can be implemented using various mechanisms e.g. Oracle API Gateway provides firewall and proxy services along with comprehensive security, auditing, throttling benefits. If a firewall already exists, then Oracle Service Bus or Oracle HTTP Server virtual hosts can provide reverse proxy implementations on the DMZ. Custom built implementations are also possible if specific functionality (such as message store-n-forward) is needed. In the home analogy, this pattern sits in between cutting mail slots and handing over keys. Instead, you install (and maintain) a mailbox in your home premises outside your door. The post office delivers the parcels in your mailbox, from where you can securely retrieve it. Pros: Very secure, very flexible Cons: Introduces a new software component, needs DMZ deployment and management Pattern: On-Premise Agent (Tunneling) A light weight "agent" software sits behind the firewall and initiates the communication with the cloud, thereby avoiding firewall issues. It then maintains a bi-directional connection either with pull or push based approaches using (or abusing, depending on your viewpoint) the HTTP protocol. Programming protocols such as Comet, WebSockets, HTTP CONNECT, HTTP SSH Tunneling etc. are possible implementation options. In the home analogy, a resident receives the parcel from the postal worker by opening the door, however you still take precautions with chain locks and package inspections. Pros: Light weight software, IT doesn't need to setup anything Cons: May bypass critical firewall checks e.g. virus scans, separate software download, proliferation of non-IT managed software Conclusion The patterns above are some of the most commonly encountered ones for cloud to on-premise integration. Selecting the right pattern for your project involves looking at your scalability needs, security restrictions, sync vs asynchronous implementation, near real-time vs batch expectations, cloud provider capabilities, budget, and more. In some cases, the basic "Pull from Cloud" may be acceptable, whereas in others, an extensive VPN topology may be well justified. For more details on the Oracle cloud integration strategy, download this white paper.

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  • ADF Business Components

    - by Arda Eralp
    ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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  • What do the participants say about the Open Day in South Africa?

    - by Maria Sandu
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 On the 26th of September, a group of students who were specifically selected to attend an Open day at Oracle South Africa, joined us at our offices in Woodmead, Johannesburg. The Conference room was filled with inquisitive minds. What we had in store for them was a detailed presentation about Oracle which was delivered by Zuko - Cluster Leader: Tech GB South Africa. The student’s many questions were all answered especially when we started addressing the opportunities we have and detailed information on our Graduate Programme. Our employees then came to talk about their experience. This allowed all the students to have an integrated learning experience. By inviting the students to walk around our Oracle Offices allowed them to see, talk, experience a bit of the culture and ask more questions. Here is some of the feedback from the attendees: Maxwell Moloi: “The open day truly served its purpose and exceeded expectations in the sense that I got to find out more about Oracle and all the different opportunities it has to offer. The fact that Oracle supplies a full solution to a customer and not just part of it and how the company manages to setup professional development for their employees is what entices me to want to join the rapidly growing team of Oracle.” Nqobile Mabaso: “I found the open day to be quite informative and enlightening because coming from a marketing background I could apply the knowledge I got from varsity to the Company I was able to point out what they do as part of their corporate social responsibility (Oracle recently partnered with the department of education to build a school), how Oracle emphasizes on relationship building because they know they sell to people and not companies and how they offer the full stack of solutions which gives them a competitive advantage over their competitors.” Nondumiso Mvelase: “The Open Day was a wonderful experience for me especially because I have never been part of an Open Day before, so it was absolutely amazing for me. It gave me a good idea of how it is to be part of Oracle. We were served with lovely breakfast and lunch which I enjoyed. I wish the Open Day went on for a whole week. Seeing and hearing from 2013 Graduates, telling us about their experience within Oracle was very inspiring to me. They were encouraging us to work hard if we ever got the opportunity they had. After hearing this from them I will definitely not take it for granted.” Itumeleng Moraka: “Before I walked into the Oracle offices all that was in my mind was databases and cloud storage. I was then surrounded by passionate, enthusiastic and welcoming employees. I came across a positive energy within the multinational company. I realized that Oracle is not a company that operates in survival mode. This may sound idealistic, but they operate in a non-traditional way investing more into innovation, they stay focused on what matters most about where technology is going and at the same time they are not losing sight of how their products make a difference in the world.” For more information on how to be part of the Oracle Graduate Programme please follow us on Facebook! https://www.facebook.com/CampusAtOracle /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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  • The design of a generic data synchronizer, or, an [object] that does [actions] with the aid of [helpers]

    - by acheong87
    I'd like to create a generic data-source "synchronizer," where data-source "types" may include MySQL databases, Google Spreadsheets documents, CSV files, among others. I've been trying to figure out how to structure this in terms of classes and interfaces, keeping in mind (what I've read about) composition vs. inheritance and is-a vs. has-a, but each route I go down seems to violate some principle. For simplicity, assume that all data-sources have a header-row-plus-data-rows format. For example, assume that the first rows of Google Spreadsheets documents and CSV files will have column headers, a.k.a. "fields" (to parallel database fields). Also, eventually, I would like to implement this in PHP, but avoiding language-specific discussion would probably be more productive. Here's an overview of what I've tried. Part 1/4: ISyncable class CMySQL implements ISyncable GetFields() // sql query, pdo statement, whatever AddFields() RemFields() ... _dbh class CGoogleSpreadsheets implements ISyncable GetFields() // zend gdata api AddFields() RemFields() ... _spreadsheetKey _worksheetId class CCsvFile implements ISyncable GetFields() // read from buffer AddFields() RemFields() ... _buffer interface ISyncable GetFields() AddFields($field1, $field2, ...) RemFields($field1, $field2, ...) ... CanAddFields() // maybe the spreadsheet is locked for write, or CanRemFields() // maybe no permission to alter a database table ... AddRow() ModRow() RemRow() ... Open() Close() ... First Question: Does it make sense to use an interface, as above? Part 2/4: CSyncer Next, the thing that does the syncing. class CSyncer __construct(ISyncable $A, ISyncable $B) Push() // sync A to B Pull() // sync B to A Sync() // Push() and Pull() only differ in direction; factor. // Sync()'s job is to make sure that the fields on each side // match, to add fields where appropriate and possible, to // account for different column-orderings, etc., and of // course, to add and remove rows as necessary to sync. ... _A _B Second Question: Does it make sense to define such a class, or am I treading dangerously close to the "Kingdom of Nouns"? Part 3/4: CTranslator? ITranslator? Now, here's where I actually get lost, assuming the above is passable. Sometimes, two ISyncables speak different "dialects." For example, believe it or not, Google Spreadsheets (accessed through the Google Data API "list feed") returns column headers lower-cased and stripped of all spaces and symbols! That is, sys_TIMESTAMP is systimestamp, as far as my code can tell. (Yes, I am aware that the "cell feed" does not strip the name so; however cell-by-cell manipulation is too slow for what I'm doing.) One can imagine other hypothetical examples. Perhaps even the data itself can be in different "dialects." But let's take it as given for now, and not argue this if possible. Third Question: How would you implement "translation"? Note: Taking all this as an exercise, I'm more interested in the "idealized" design, rather than the practical one. (God knows that shipped sailed when I began this project.) Part 4/4: Further Thought Here's my train of thought to demonstrate I've thunk, albeit unfruitfully: First, I thought, primitively, "I'll just modify CMySQL::GetFields() to lower-case and strip field names so they're compatible with Google Spreadsheets." But of course, then my class should really be called, CMySQLForGoogleSpreadsheets, and that can't be right. So, the thing which translates must exist outside of an ISyncable implementor. And surely it can't be right to make each translation a method in CSyncer. If it exists outside of both ISyncable and CSyncer, then what is it? (Is it even an "it"?) Is it an abstract class, i.e. abstract CTranslator? Is it an interface, since a translator only does, not has, i.e. interface ITranslator? Does it even require instantiation? e.g. If it's an ITranslator, then should its translation methods be static? (I learned what "late static binding" meant, today.) And, dear God, whatever it is, how should a CSyncer use it? Does it "have" it? Is it, "it"? Who am I? ...am I, "I"? I've attempted to break up the question into sub-questions, but essentially my question is singular: How does one implement an object A that conceptually "links" (has) two objects b1 and b2 that share a common interface B, where certain pairs of b1 and b2 require a helper, e.g. a translator, to be handled by A? Something tells me that I've overcomplicated this design, or violated a principle much higher up. Thank you all very much for your time and any advice you can provide.

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  • Cloud Deployment Models

    - by B R Clouse
    Normal 0 false false false EN-US X-NONE X-NONE As the cloud paradigm grows in depth and breadth, more readers are approaching the topic for the first time, or from a new perspective.  This blog is a basic review of  cloud deployment models, to help orient newcomers and neophytes. Most cloud deployments today are either private or public. It is also possible to connect a private cloud and a public cloud to form a hybrid cloud. A private cloud is for the exclusive use of an organization. Enterprises, universities and government agencies throughout the world are using private clouds. Some have designed, built and now manage their private clouds. Others use a private cloud that was built by and is now managed by a provider, hosted either onsite or at the provider’s datacenter. Because private clouds are for exclusive use, they are usually the option chosen by organizations with concerns about data security and guaranteed performance. Public clouds are open to anyone with an Internet connection. Because they require no capital investment from their users, they are particularly attractive to companies with limited resources in less regulated environments and for temporary workloads such as development and test environments. Public clouds offer a range of products, from end-user software packages to more basic services such as databases or operating environments. Public clouds may also offer cloud services such as a disaster recovery for a private cloud, or the ability to “cloudburst” a temporary workload spike from a private cloud to a public cloud. These are examples of a hybrid cloud. These are most feasible when the private and public clouds are built with similar technologies. Usually people think of a public cloud in terms of a user role, e.g., “Which public cloud should I consider using?” But someone needs to own and manage that public cloud. The company who owns and operates a public cloud is known as a public cloud provider. Oracle Database Cloud Service, Amazon RDS, database.com and Savvis Symphony Database are examples of public cloud database services. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} When evaluating deployment models, be aware that you can use any or all of the available options. Some workloads may be best-suited for a private cloud, some for a public or hybrid cloud. And you might deploy multiple private clouds in your organization. If you are going to combine multiple clouds, then you want to make sure that each cloud is based on a consistent technology portfolio and architecture. This simplifies management and gives you the greatest flexibility in moving resources and workloads among your different clouds. Oracle’s portfolio of cloud products and services enables both deployment models. Oracle can manage either model. Universities, government agencies and companies in all types of business everywhere in the world are using clouds built with the Oracle portfolio. By employing a consistent portfolio, these customers are able to run all of their workloads – from test and development to the most mission-critical -- in a consistent manner: One Enterprise Cloud, powered by Oracle.   /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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  • Data Source Security Part 1

    - by Steve Felts
    I’ve written a couple of articles on how to store data source security credentials using the Oracle wallet.  I plan to write a few articles on the various types of security available to WebLogic Server (WLS) data sources.  There are more options than you might think! There have been several enhancements in this area in WLS 10.3.6.  There are a couple of more enhancements planned for release WLS 12.1.2 that I will include here for completeness.  This isn’t intended as a teaser.  If you call your Oracle support person, you can get them now as minor patches to WLS 10.3.6.   The current security documentation is scattered in a few places, has a few incorrect statements, and is missing a few topics.  It also seems that the knowledge of how to apply some of these features isn’t written down.  The goal of these articles is to talk about WLS data source security in a unified way and to introduce some approaches to using the available features.  Introduction to WebLogic Data Source Security Options By default, you define a single database user and password for a data source.  You can store it in the data source descriptor or make use of the Oracle wallet.  This is a very simple and efficient approach to security.  All of the connections in the connection pool are owned by this user and there is no special processing when a connection is given out.  That is, it’s a homogeneous connection pool and any request can get any connection from a security perspective (there are other aspects like affinity).  Regardless of the end user of the application, all connections in the pool use the same security credentials to access the DBMS.   No additional information is needed when you get a connection because it’s all available from the data source descriptor (or wallet). java.sql.Connection conn =  mydatasource.getConnection(); Note: You can enter the password as a name-value pair in the Properties field (this not permitted for production environments) or you can enter it in the Password field of the data source descriptor. The value in the Password field overrides any password value defined in the Properties passed to the JDBC Driver when creating physical database connections. It is recommended that you use the Password attribute in place of the password property in the properties string because the Password value is encrypted in the configuration file (stored as the password-encrypted attribute in the jdbc-driver-params tag in the module file) and is hidden in the administration console.  The Properties and Password fields are located on the administration console Data Source creation wizard or Data Source Configuration tab. The JDBC API can also be used to programmatically specify a database user name and password as in the following.  java.sql.Connection conn = mydatasource.getConnection(“user”, “password”); According to the JDBC specification, it’s supposed to take a database user and associated password but different vendors implement this differently.  WLS, by default, treats this as an application server user and password.  The pair is authenticated to see if it’s a valid user and that user is used for WLS security permission checks.  By default, the user is then mapped to a database user and password using the data source credential mapper, so this API sort of follows the specification but database credentials are one-step removed from the application code.  More details and the rationale are described later. While the default approach is simple, it does mean that only one database user is doing all of the work.  You can’t figure out who actually did the update and you can’t restrict SQL operations by who is running the operation, at least at the database level.   Any type of per-user logic will need to be in the application code instead of having the database do it.  There are various WLS data source features that can be configured to provide some per-user information about the operations to the database. WebLogic Data Source Security Options This table describes the features available for WebLogic data sources to configure database security credentials and a brief description.  It also captures information about the compatibility of these features with one another. Feature Description Can be used with Can’t be used with User authentication (default) Default getConnection(user, password) behavior – validate the input and use the user/password in the descriptor. Set client identifier Proxy Session, Identity pooling, Use database credentials Use database credentials Instead of using the credential mapper, use the supplied user and password directly. Set client identifier, Proxy session, Identity pooling User authentication, Multi Data Source Set Client Identifier Set a client identifier property associated with the connection (Oracle and DB2 only). Everything Proxy Session Set a light-weight proxy user associated with the connection (Oracle-only). Set client identifier, Use database credentials Identity pooling, User authentication Identity pooling Heterogeneous pool of connections owned by specified users. Set client identifier, Use database credentials Proxy session, User authentication, Labeling, Multi-datasource, Active GridLink Note that all of these features are available with both XA and non-XA drivers. Currently, the Proxy Session and Use Database Credentials options are on the Oracle tab of the Data Source Configuration tab of the administration console (even though the Use Database Credentials feature is not just for Oracle databases – oops).  The rest of the features are on the Identity tab of the Data Source Configuration tab in the administration console (plan on seeing them all in one place in the future). The subsequent articles will describe these features in more detail.  Keep referring back to this table to see the big picture.

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  • Java EE 7 Survey Results!

    - by reza_rahman
    On November 8th, the Java EE EG posted a survey to gather broad community feedback on a number of critical open issues. For reference, you can find the original survey here. We kept the survey open for about three weeks until November 30th. To our delight, over 1100 developers took time out of their busy lives to let their voices be heard! The results of the survey were sent to the EG on December 12th. The subsequent EG discussion is available here. The exact summary sent to the EG is available here. We would like to take this opportunity to thank each and every one the individuals who took the survey. It is very appreciated, encouraging and worth it's weight in gold. In particular, I tried to capture just some of the high-quality, intelligent, thoughtful and professional comments in the summary to the EG. I highly encourage you to continue to stay involved, perhaps through the Adopt-a-JSR program. We would also like to sincerely thank java.net, JavaLobby, TSS and InfoQ for helping spread the word about the survey. Below is a brief summary of the results... APIs to Add to Java EE 7 Full/Web Profile The first question asked which of the four new candidate APIs (WebSocket, JSON-P, JBatch and JCache) should be added to the Java EE 7 Full and Web profile respectively. As the following graph shows, there was significant support for adding all the new APIs to the full profile: Support is relatively the weakest for Batch 1.0, but still good. A lot of folks saw WebSocket 1.0 as a critical technology with comments such as this one: "A modern web application needs Web Sockets as first class citizens" While it is clearly seen as being important, a number of commenters expressed dissatisfaction with the lack of a higher-level JSON data binding API as illustrated by this comment: "How come we don't have a Data Binding API for JSON" JCache was also seen as being very important as expressed with comments like: "JCache should really be that foundational technology on which other specs have no fear to depend on" The results for the Web Profile is not surprising. While there is strong support for adding WebSocket 1.0 and JSON-P 1.0 to the Web Profile, support for adding JCache 1.0 and Batch 1.0 is relatively weak. There was actually significant opposition to adding Batch 1. 0 (with 51.8% casting a 'No' vote). Enabling CDI by Default The second question asked was whether CDI should be enabled in Java EE environments by default. A significant majority of 73.3% developers supported enabling CDI, only 13.8% opposed. Comments such as these two reflect a strong general support for CDI as well as a desire for better Java EE alignment with CDI: "CDI makes Java EE quite valuable!" "Would prefer to unify EJB, CDI and JSF lifecycles" There is, however, a palpable concern around the performance impact of enabling CDI by default as exemplified by this comment: "Java EE projects in most cases use CDI, hence it is sensible to enable CDI by default when creating a Java EE application. However, there are several issues if CDI is enabled by default: scanning can be slow - not all libs use CDI (hence, scanning is not needed)" Another significant concern appears to be around backwards compatibility and conflict with other JSR 330 implementations like Spring: "I am leaning towards yes, however can easily imagine situations where errors would be caused by automatically activating CDI, especially in cases of backward compatibility where another DI engine (such as Spring and the like) happens to use the same mechanics to inject dependencies and in that case there would be an overlap in injections and probably an uncertain outcome" Some commenters such as this one attempt to suggest solutions to these potential issues: "If you have Spring in use and use javax.inject.Inject then you might get some unexpected behavior that could be equally confusing. I guess there will be a way to switch CDI off. I'm tempted to say yes but am cautious for this reason" Consistent Usage of @Inject The third question was around using CDI/JSR 330 @Inject consistently vs. allowing JSRs to create their own injection annotations. A slight majority of 53.3% developers supported using @Inject consistently across JSRs. 28.8% said using custom injection annotations is OK, while 18.0% were not sure. The vast majority of commenters were strongly supportive of CDI and general Java EE alignment with CDI as illistrated by these comments: "Dependency Injection should be standard from now on in EE. It should use CDI as that is the DI mechanism in EE and is quite powerful. Having a new JSR specific DI mechanism to deal with just means more reflection, more proxies. JSRs should also be constructed to allow some of their objects Injectable. @Inject @TransactionalCache or @Inject @JMXBean etc...they should define the annotations and stereotypes to make their code less procedural. Dog food it. If there is a shortcoming in CDI for a JSR fix it and we will all be grateful" "We're trying to make this a comprehensive platform, right? Injection should be a fundamental part of the platform; everything else should build on the same common infrastructure. Each-having-their-own is just a recipe for chaos and having to learn the same thing 10 different ways" Expanding the Use of @Stereotype The fourth question was about expanding CDI @Stereotype to cover annotations across Java EE beyond just CDI. A significant majority of 62.3% developers supported expanding the use of @Stereotype, only 13.3% opposed. A majority of commenters supported the idea as well as the theme of general CDI/Java EE alignment as expressed in these examples: "Just like defining new types for (compositions of) existing classes, stereotypes can help make software development easier" "This is especially important if many EJB services are decoupled from the EJB component model and can be applied via individual annotations to Java EE components. @Stateless is a nicely compact annotation. Code will not improve if that will have to be applied in the future as @Transactional, @Pooled, @Secured, @Singlethreaded, @...." Some, however, expressed concerns around increased complexity such as this commenter: "Could be very convenient, but I'm afraid if it wouldn't make some important class annotations less visible" Expanding Interceptor Use The final set of questions was about expanding interceptors further across Java EE... A very solid 96.3% of developers wanted to expand interceptor use to all Java EE components. 35.7% even wanted to expand interceptors to other Java EE managed classes. Most developers (54.9%) were not sure if there is any place that injection is supported that should not support interceptors. 32.8% thought any place that supports injection should also support interceptors. Only 12.2% were certain that there are places where injection should be supported but not interceptors. The comments reflected the diversity of opinions, generally supportive of interceptors: "I think interceptors are as fundamental as injection and should be available anywhere in the platform" "The whole usage of interceptors still needs to take hold in Java programming, but it is a powerful technology that needs some time in the Sun. Basically it should become part of Java SE, maybe the next step after lambas?" A distinct chain of thought separated interceptors from filters and listeners: "I think that the Servlet API already provides a rich set of possibilities to hook yourself into different Servlet container events. I don't find a need to 'pollute' the Servlet model with the Interceptors API"

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  • Local LINQtoSQL Database For Your Windows Phone 7 Application

    - by Tim Murphy
    There aren’t many applications that are of value without having some for of data store.  In Windows Phone development we have a few options.  You can store text directly to isolated storage.  You can also use a number of third party libraries to create or mimic databases in isolated storage.  With Mango we gained the ability to have a native .NET database approach which uses LINQ to SQL.  In this article I will try to bring together the components needed to implement this last type of data store and fill in some of the blanks that I think other articles have left out. Defining A Database The first things you are going to need to do is define classes that represent your tables and a data context class that is used as the overall database definition.  The table class consists of column definitions as you would expect.  They can have relationships and constraints as with any relational DBMS.  Below is an example of a table definition. First you will need to add some assembly references to the code file. using System.ComponentModel;using System.Data.Linq;using System.Data.Linq.Mapping; You can then add the table class and its associated columns.  It needs to implement INotifyPropertyChanged and INotifyPropertyChanging.  Each level of the class needs to be decorated with the attribute appropriate for that part of the definition.  Where the class represents the table the properties represent the columns.  In this example you will see that the column is marked as a primary key and not nullable with a an auto generated value. You will also notice that the in the column property’s set method It uses the NotifyPropertyChanging and NotifyPropertyChanged methods in order to make sure that the proper events are fired. [Table]public class MyTable: INotifyPropertyChanged, INotifyPropertyChanging{ public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if(PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public event PropertyChangingEventHandler PropertyChanging; private void NotifyPropertyChanging(string propertyName) { if(PropertyChanging != null) { PropertyChanging(this, new PropertyChangingEventArgs(propertyName)); } } private int _TableKey; [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)] public int TableKey { get { return _TableKey; } set { NotifyPropertyChanging("TableKey"); _TableKey = value; NotifyPropertyChanged("TableKey"); } } The last part of the database definition that needs to be created is the data context.  This is a simple class that takes an isolated storage location connection string its constructor and then instantiates tables as public properties. public class MyDataContext: DataContext{ public MyDataContext(string connectionString): base(connectionString) { MyRecords = this.GetTable<MyTable>(); } public Table<MyTable> MyRecords;} Creating A New Database Instance Now that we have a database definition it is time to create an instance of the data context within our Windows Phone app.  When your app fires up it should check if the database already exists and create an instance if it does not.  I would suggest that this be part of the constructor of your ViewModel. db = new MyDataContext(connectionString);if(!db.DatabaseExists()){ db.CreateDatabase();} The next thing you have to know is how the connection string for isolated storage should be constructed.  The main sticking point I have found is that the database cannot be created unless the file mode is read/write.  You may have different connection strings but the initial one needs to be similar to the following. string connString = "Data Source = 'isostore:/MyApp.sdf'; File Mode = read write"; Using you database Now that you have done all the up front work it is time to put the database to use.  To make your life a little easier and keep proper separation between your view and your viewmodel you should add a couple of methods to the viewmodel.  These will do the CRUD work of your application.  What you will notice is that the SubmitChanges method is the secret sauce in all of the methods that change data. private myDataContext myDb;private ObservableCollection<MyTable> _viewRecords;public ObservableCollection<MyTable> ViewRecords{ get { return _viewRecords; } set { _viewRecords = value; NotifyPropertyChanged("ViewRecords"); }}public void LoadMedstarDbData(){ var tempItems = from MyTable myRecord in myDb.LocalScans select myRecord; ViewRecords = new ObservableCollection<MyTable>(tempItems);}public void SaveChangesToDb(){ myDb.SubmitChanges();}public void AddMyTableItem(MyTable newScan){ myDb.LocalScans.InsertOnSubmit(newScan); myDb.SubmitChanges();}public void DeleteMyTableItem(MyTable newScan){ myDb.LocalScans.DeleteOnSubmit(newScan); myDb.SubmitChanges();} Updating existing database What happens when you need to change the structure of your database?  Unfortunately you have to add code to your application that checks the version of the database which over time will create some pollution in your codes base.  On the other hand it does give you control of the update.  In this example you will see the DatabaseSchemaUpdater in action.  Assuming we added a “Notes” field to the MyTable structure, the following code will check if the database is the latest version and add the field if it isn’t. if(!myDb.DatabaseExists()){ myDb.CreateDatabase();}else{ DatabaseSchemaUpdater dbUdater = myDb.CreateDatabaseSchemaUpdater(); if(dbUdater.DatabaseSchemaVersion < 2) { dbUdater.AddColumn<MyTable>("Notes"); dbUdater.DatabaseSchemaVersion = 2; dbUdater.Execute(); }} Summary This approach does take a fairly large amount of work, but I think the end product is robust and very native for .NET developers.  It turns out to be worth the investment. del.icio.us Tags: Windows Phone,Windows Phone 7,LINQ to SQL,LINQ,Database,Isolated Storage

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  • Adaptive Connections For ADFBC

    - by Duncan Mills
    Some time ago I wrote an article on Adaptive Bindings showing how the pageDef for a an ADF UI does not have to be wedded to a fixed data control or collection / View Object. This article has proved pretty popular, so as a follow up I wanted to cover another "Adaptive" feature of your ADF applications, the ability to make multiple different connections from an Application Module, at runtime. Now, I'm sure you'll be aware that if you define your application to use a data-source rather than a hard-coded JDBC connection string, then you have the ability to change the target of that data-source after deployment to point to a different database. So that's great, but the reality of that is that this single connection is effectively fixed within the application right?  Well no, this it turns out is a common misconception. To be clear, yes a single instance of an ADF Application Module is associated with a single connection but there is nothing to stop you from creating multiple instances of the same Application Module within the application, all pointing at different connections.  If fact this has been possible for a long time using a custom extension point with code that which extends oracle.jbo.http.HttpSessionCookieFactory. This approach, however, involves writing code and no-one likes to write any more code than they need to, so, is there an easier way? Yes indeed.  It is in fact  a little publicized feature that's available in all versions of 11g, the ELEnvInfoProvider. What Does it Do?  The ELEnvInfoProvider  is  a pre-existing class (the full path is  oracle.jbo.client.ELEnvInfoProvider) which you can plug into your ApplicationModule configuration using the jbo.envinfoprovider property. Visuallty you can set this in the editor, or you can also set it directly in the bc4j.xcfg (see below for an example) . Once you have plugged in this envinfoprovider, here's the fun bit, rather than defining the hard-coded name of a datasource instead you can plug in a EL expression for the connection to use.  So what's the benefit of that? Well it allows you to defer the selection of a connection until the point in time that you instantiate the AM. To define the expression itself you'll need to do a couple of things: First of all you'll need a managed bean of some sort – e.g. a sessionScoped bean defined in your ViewController project. This will need a getter method that returns the name of the connection. Now this connection itself needs to be defined in your Application Server, and can be managed through Enterprise Manager, WLST or through MBeans. (You may need to read the documentation [http://docs.oracle.com/cd/E28280_01/web.1111/b31974/deployment_topics.htm#CHDJGBDD] here on how to configure connections at runtime if you're not familiar with this)   The EL expression (e.g. ${connectionManager.connection} is then defined in the configuration by editing the bc4j.xcfg file (there is a hyperlink directly to this file on the configuration editing screen in the Application Module editor). You simply replace the hardcoded JDBCName value with the expression.  So your cfg file would end up looking something like this (notice the reference to the ELEnvInfoProvider that I talked about earlier) <BC4JConfig version="11.1" xmlns="http://xmlns.oracle.com/bc4j/configuration">   <AppModuleConfigBag ApplicationName="oracle.demo.model.TargetAppModule">   <AppModuleConfig DeployPlatform="LOCAL"  JDBCName="${connectionManager.connection}" jbo.project="oracle.demo.model.Model" name="TargetAppModuleLocal" ApplicationName="oracle.demo.model.TargetAppModule"> <AM-Pooling jbo.doconnectionpooling="true"/> <Database jbo.locking.mode="optimistic">       <Security AppModuleJndiName="oracle.demo.model.TargetAppModule"/>    <Custom jbo.envinfoprovider="oracle.jbo.client.ELEnvInfoProvider"/> </AppModuleConfig> </AppModuleConfigBag> </BC4JConfig> Still Don't Quite Get It? So far you might be thinking, well that's fine but what difference does it make if the connection is resolved "just in time" rather than up front and changed as required through Enterprise Manager? Well a trivial example would be where you have a single application deployed to your application server, but for different users you want to connect to different databases. Because, the evaluation of the connection is deferred until you first reference the AM you have a decision point that can take the user identity into account. However, think about it for a second.  Under what circumstances does a new AM get instantiated? Well at the first reference of the AM within the application yes, but also whenever a Task Flow is entered -  if the data control scope for the Task Flow is ISOLATED.  So the reality is, that on a single screen you can embed multiple Task Flows, all of which are pointing at different database connections concurrently. Hopefully you'll find this feature useful, let me know... 

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  • Capistrano asks for SSH password when deploying from local machine to server

    - by GhostRider
    When I try to ssh to a server, I'm able to do it as my id_rsa.pub key is added to the authorized keys in the server. Now when I try to deploy my code via Capistrano to the server from my local project folder, the server asks for a password. I'm unable to understand what could be the issue if I'm able to ssh and unable to deploy to the same server. $ cap deploy:setup "no seed data" triggering start callbacks for `deploy:setup' * 13:42:18 == Currently executing `multistage:ensure' *** Defaulting to `development' * 13:42:18 == Currently executing `development' * 13:42:18 == Currently executing `deploy:setup' triggering before callbacks for `deploy:setup' * 13:42:18 == Currently executing `db:configure_mongoid' * executing "mkdir -p /home/deploy/apps/development/flyingbird/shared/config" servers: ["dev1.noob.com", "176.9.24.217"] Password: Cap script: # gem install capistrano capistrano-ext capistrano_colors begin; require 'capistrano_colors'; rescue LoadError; end require "bundler/capistrano" # RVM bootstrap # $:.unshift(File.expand_path('./lib', ENV['rvm_path'])) require 'rvm/capistrano' set :rvm_ruby_string, 'ruby-1.9.2-p290' set :rvm_type, :user # or :user # Application setup default_run_options[:pty] = true # allow pseudo-terminals ssh_options[:forward_agent] = true # forward SSH keys (this will use your SSH key to get the code from git repository) ssh_options[:port] = 22 set :ip, "dev1.noob.com" set :application, "flyingbird" set :repository, "repo-path" set :scm, :git set :branch, fetch(:branch, "master") set :deploy_via, :remote_cache set :rails_env, "production" set :use_sudo, false set :scm_username, "user" set :user, "user1" set(:database_username) { application } set(:production_database) { application + "_production" } set(:staging_database) { application + "_staging" } set(:development_database) { application + "_development" } role :web, ip # Your HTTP server, Apache/etc role :app, ip # This may be the same as your `Web` server role :db, ip, :primary => true # This is where Rails migrations will run # Use multi-staging require "capistrano/ext/multistage" set :stages, ["development", "staging", "production"] set :default_stage, rails_env before "deploy:setup", "db:configure_mongoid" # Uncomment if you use any of these databases after "deploy:update_code", "db:symlink_mongoid" after "deploy:update_code", "uploads:configure_shared" after "uploads:configure_shared", "uploads:symlink" after 'deploy:update_code', 'bundler:symlink_bundled_gems' after 'deploy:update_code', 'bundler:install' after "deploy:update_code", "rvm:trust_rvmrc" # Use this to update crontab if you use 'whenever' gem # after "deploy:symlink", "deploy:update_crontab" if ARGV.include?("seed_data") after "deploy", "db:seed" else p "no seed data" end #Custom tasks to handle resque and redis restart before "deploy", "deploy:stop_workers" after "deploy", "deploy:restart_redis" after "deploy", "deploy:start_workers" after "deploy", "deploy:cleanup" 'Create symlink for public uploads' namespace :uploads do task :symlink do run <<-CMD rm -rf #{release_path}/public/uploads && mkdir -p #{release_path}/public && ln -nfs #{shared_path}/public/uploads #{release_path}/public/uploads CMD end task :configure_shared do run "mkdir -p #{shared_path}/public" run "mkdir -p #{shared_path}/public/uploads" end end namespace :rvm do desc 'Trust rvmrc file' task :trust_rvmrc do run "rvm rvmrc trust #{current_release}" end end namespace :db do desc "Create mongoid.yml in shared path" task :configure_mongoid do db_config = <<-EOF defaults: &defaults host: localhost production: <<: *defaults database: #{production_database} staging: <<: *defaults database: #{staging_database} EOF run "mkdir -p #{shared_path}/config" put db_config, "#{shared_path}/config/mongoid.yml" end desc "Make symlink for mongoid.yml" task :symlink_mongoid do run "ln -nfs #{shared_path}/config/mongoid.yml #{release_path}/config/mongoid.yml" end desc "Fill the database with seed data" task :seed do run "cd #{current_path}; RAILS_ENV=#{default_stage} bundle exec rake db:seed" end end namespace :bundler do desc "Symlink bundled gems on each release" task :symlink_bundled_gems, :roles => :app do run "mkdir -p #{shared_path}/bundled_gems" run "ln -nfs #{shared_path}/bundled_gems #{release_path}/vendor/bundle" end desc "Install bundled gems " task :install, :roles => :app do run "cd #{release_path} && bundle install --deployment" end end namespace :deploy do task :start, :roles => :app do run "touch #{current_path}/tmp/restart.txt" end desc "Restart the app" task :restart, :roles => :app do run "touch #{current_path}/tmp/restart.txt" end desc "Start the workers" task :stop_workers do run "cd #{current_path}; RAILS_ENV=#{default_stage} bundle exec rake resque:stop_workers" end desc "Restart Redis server" task :restart_redis do "/etc/init.d/redis-server restart" end desc "Start the workers" task :start_workers do run "cd #{current_path}; RAILS_ENV=#{default_stage} bundle exec rake resque:start_workers" end end

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  • SQL Server Issue: Could not allocate space for object ... primary filegroup is full

    - by Luke
    Trying to figure out a problem at an office that has SQL Server 2005 installed on Windows SBS Server 2008. Here's the setup: It's an office, and the person who set this all up is nowhere to be found. I'm the best hope they have... One of the programs they use on a workstation gives them an error of "Could not allocate space for object 'Billing' in database "MyDatabase" because primary filegroup is full" when trying to save an entry in their software. I searched around for hours, looking for possible solutions. One was to check for available disk space, and another was to defrag. I checked the hard drives on the server, and there is plenty of space free. I also defragged, which may have helped the problem somewhat. It's hard to say, because it seems like with the nature of the error, if you try over and over you might get it to actually save. My next step was to try to see if autogrowth was enabled on the database. This would seem to be a likely / possible solution, but I can't access the database! If I run the SQL Management Studio, I can log in as my Windows user and view the list of databases. However, if I try to do anything (actually view the database, view the properties, add or edit users), I get errors that I don't have permission. For what it's worth, I also tried runing Management Studio as Administrator, in case that would help. No difference, though. Now, what I'm guessing is going on -- from my limited knowledge of SQL and from reading online -- is that though I'm logged in as a Windows administrator, that account does NOT have SQL access. I do see a list of SQL users, including SA, but I again don't have permission to add one or to change the password on an existing one. And nobody at the office has any idea what the SQL passwords could be. So... here's my thinking thus far: 1 - The "Could not allocate" error likely points to a database that needs to be allowed to autogrow. Especially since I verified there is plenty of free space and the HD has been defragmented. 2 - Enabling autogrow would be very easy to do if I had the proper access within SQL Management Stuido. That leads me to this link: http://blogs.technet.com/b/sqlman/archive/2011/06/14/tips-amp-tricks-you-have-lost-access-to-sql-server-now-what.aspx It sounds like it's a step-by-step guide for giving me the access I need to SQL. I'm guessing that if I followed this guide, I would be able to then log in to the SQL server via Management Studio with the proper permissions, and would be able to enable autogrow (or simply view the status of the existing database), and hopefully solve the "Could not allocate space" problem! So I guess I have a few questions: 1 - Would you guys agree with my "diagnosis"? Think I'm barking up the right tree? 2 - Is there any risk at all in hurting / disabling / wrecking the current SQL database or setup with me going through the guide to regain SQL access? I understand that per the guide, I would have to temporarily shut down SQL, so obviously it wouldn't be accessible during that time. But it wouldn't be worth the risk if there's a chance I could mess anything up... Like I said, the workstations ARE currently accessing the database somehow, but nobody knows with what login info or anything. Basically, it's set up, it works (usually), but if they had to reload the software, nobody would know how. Any feedback would be appreciated!! The problem is such that it's not an emergency for them, but an annoyance. If I could fix it, it would be wonderful. But if not, I think they'll manage, especially as they are going to eventually stop using this software. Thank you so much for your time! Luke

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  • How to correctly use DERIVE or COUNTER in munin plugins

    - by Johan
    I'm using munin to monitor my server. I've been able to write plugins for it, but only if the graph type is GAUGE. When I try COUNTER or DERIVE, no data is logged or graphed. The plugin i'm currently stuck on is for monitoring bandwidth usage, and is as follows: /etc/munin/plugins/bandwidth2 #!/bin/sh if [ "$1" = "config" ]; then echo 'graph_title Bandwidth Usage 2' echo 'graph_vlabel Bandwidth' echo 'graph_scale no' echo 'graph_category network' echo 'graph_info Bandwidth usage.' echo 'used.label Used' echo 'used.info Bandwidth used so far this month.' echo 'used.type DERIVE' echo 'used.min 0' echo 'remain.label Remaining' echo 'remain.info Bandwidth remaining this month.' echo 'remain.type DERIVE' echo 'remain.min 0' exit 0 fi cat /var/log/zen.log The contents of /var/log/zen.log are: used.value 61.3251953125 remain.value 20.0146484375 And the resulting database is: <!-- Round Robin Database Dump --><rrd> <version> 0003 </version> <step> 300 </step> <!-- Seconds --> <lastupdate> 1269936605 </lastupdate> <!-- 2010-03-30 09:10:05 BST --> <ds> <name> 42 </name> <type> DERIVE </type> <minimal_heartbeat> 600 </minimal_heartbeat> <min> 0.0000000000e+00 </min> <max> NaN </max> <!-- PDP Status --> <last_ds> 61.3251953125 </last_ds> <value> NaN </value> <unknown_sec> 5 </unknown_sec> </ds> <!-- Round Robin Archives --> <rra> <cf> AVERAGE </cf> <pdp_per_row> 1 </pdp_per_row> <!-- 300 seconds --> <params> <xff> 5.0000000000e-01 </xff> </params> <cdp_prep> <ds> <primary_value> NaN </primary_value> <secondary_value> NaN </secondary_value> <value> NaN </value> <unknown_datapoints> 0 </unknown_datapoints> </ds> </cdp_prep> <database> <!-- 2010-03-28 09:15:00 BST / 1269764100 --> <row><v> NaN </v></row> <!-- 2010-03-28 09:20:00 BST / 1269764400 --> <row><v> NaN </v></row> <!-- 2010-03-28 09:25:00 BST / 1269764700 --> <row><v> NaN </v></row> <snip> The value for last_ds is correct, it just doesn't seem to make it into the actual database. If I change DERIVE to GAUGE, it works as expected. munin-run bandwidth2 outputs the contents of /var/log/zen.log I've been all over the (sparse) docs for munin plugins, and can't find my mistake. Modifying an existing plugin didn't work for me either.

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  • Magento hosting on a budget

    - by spa
    I have to do a setup for Magento. My constraint is primarily ease of setup and fault tolerance/fail over. Furthermore costs are an issue. I have three identical physical servers to get the job done. Each server node has an i7 quad core, 16GB RAM, and 2x3TB HD in a software RAID 1 configuration. Each node runs Ubuntu 12.04. right now. I have an additional IP address which can be routed to any of these nodes. The Magento shop has max. 1000 products, 50% of it are bundle products. I would estimate that max. 100 users are active at once. This leads me to the conclusion, that performance is not top priority here. My first setup idea One node (lb) runs nginx as a load balancer. The additional IP is used with domain name and routed to this node by default. Nginx distributes the load equally to the other two nodes (shop1, shop2). Shop1 and shop2 are configured equally: each server runs Apache2 and MySQL. The Mysqls are configured with master/slave replication. My failover strategy: Lb fails = Route IP to shop1 (MySQL master), continue. Shop1 fails = Lb will handle that automatically, promote MySQL slave on shop2 to master, reconfigure Magento to use shop2 for writes, continue. Shop2 fails = Lb will handle that automatically, continue. Is this a sane strategy? Has anyone done a similar setup with Magento? My second setup idea Another way to do it would be to use drbd for storing the MySQL data files on shop1 and shop2. I understand that in this scenario only one node/MySQL instance can be active and the other is used as hot standby. So in case shop1 fails, I would start up MySQL on shop2, route the IP to shop2, and continue. I like that as the MySQL setup is easier and the nodes can be configured 99% identical. So in this case the load balancer becomes useless and I have a spare server. My third setup idea The third way might be master-master replication of MySQL databases. However, in my optinion this might be tricky, as Magento isn't build for this scenario (e.g. conflicting ids for new rows). I would not do that until I have heard of a working example. Could you give me an advice which route to follow? There seems not one "good" way to do it. E.g. I read blog posts which describe a MySQL master/slave setup for Magento, but elsewhere I read, that data might get duplicated when the slave lags behind the master (e.g. when an order is placed, a customer might get created twice). I'm kind of lost here.

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  • Cannot Start MySQL Server on Fresh MAMP Install

    - by alexpelan
    I'm using Mac OS X 10.6.2 on my Macbook Pro. I can get the apache server to start, but not the mysql server, on both the default apache and default MAMP ports. When I try to go to my start page, I get the message "Error: Could not connect to MySQL server!" . Here's what's in my mysql error log: 00513 02:00:07 mysqld_safe mysqld from pid file /Applications/MAMP/tmp/mysql/mysql.pid ended 100513 02:00:16 mysqld_safe Starting mysqld daemon with databases from /Applications/MAMP/db/mysql 100513 2:00:16 [Warning] The syntax '--log_slow_queries' is deprecated and will be removed in a future release. Please use '--slow_query_log'/'--slow_query_log_file' instead. 100513 2:00:16 [Warning] You have forced lower_case_table_names to 0 through a command-line option, even though your file system '/Applications/MAMP/db/mysql/' is case insensitive. This means that you can corrupt a MyISAM table by accessing it with different cases. You should consider changing lower_case_table_names to 1 or 2 100513 2:00:16 [Warning] One can only use the --user switch if running as root 100513 2:00:16 [Note] Plugin 'FEDERATED' is disabled. 100513 2:00:16 [Note] Plugin 'ndbcluster' is disabled. InnoDB: Error: log file /usr/local/mysql/data/ib_logfile0 is of different size 0 5242880 bytes InnoDB: than specified in the .cnf file 0 16777216 bytes! 100513 2:00:16 [ERROR] Plugin 'InnoDB' init function returned error. 100513 2:00:16 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 100513 2:00:16 [ERROR] /Applications/MAMP/Library/libexec/mysqld: unknown option '--skip-bdb' 100513 2:00:16 [ERROR] Aborting 100513 2:00:16 [Note] /Applications/MAMP/Library/libexec/mysqld: Shutdown complete 100513 02:00:16 mysqld_safe mysqld from pid file /Applications/MAMP/tmp/mysql/mysql.pid ended A couple of things: 1) There are a bunch of different .cnf files that come with MAMP (my-huge, my-medium, etc.)...how can I tell which one is actually being used? 2) I deleted the ib_logfile0 and ib_logfile1 as recommended by another post on serverfault, and then ended up with more errors: 100519 16:01:30 InnoDB: Log file /usr/local/mysql/data/ib_logfile0 did not exist: new to be created InnoDB: Setting log file /usr/local/mysql/data/ib_logfile0 size to 16 MB InnoDB: Database physically writes the file full: wait... 100519 16:01:30 InnoDB: Log file /usr/local/mysql/data/ib_logfile1 did not exist: new to be created InnoDB: Setting log file /usr/local/mysql/data/ib_logfile1 size to 16 MB InnoDB: Database physically writes the file full: wait... InnoDB: The log sequence number in ibdata files does not match InnoDB: the log sequence number in the ib_logfiles! 100519 16:01:31 InnoDB: Database was not shut down normally! InnoDB: Starting crash recovery. InnoDB: Reading tablespace information from the .ibd files... InnoDB: Restoring possible half-written data pages from the doublewrite InnoDB: buffer... 100519 16:01:31 InnoDB: Started; log sequence number 0 44556 100519 16:01:31 [ERROR] /Applications/MAMP/Library/libexec/mysqld: unknown option '--skip-bdb' 100519 16:01:31 [ERROR] Aborting And then I got this the next time I tried to run it: InnoDB: Unable to lock /usr/local/mysql/data/ibdata1, error: 35 InnoDB: Check that you do not already have another mysqld process InnoDB: using the same InnoDB data or log files. Sorry that this is a lot of information, but I don't want to leave anything out. Thanks.

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  • Performance issues when using SSD for a developer notebook (WAMP/LAMP stack)?

    - by András Szepesházi
    I'm a web application developer using my notebook as a standalone development environment (WAMP stack). I just switched from a Core2-duo Vista 32 bit notebook with 2Gb RAM and SATA HDD, to an i5-2520M Win7 64 bit with 4Gb RAM and 128 GB SDD (Corsair P3 128). My initial experience was what I expected, fast boot, quick load of all the applications (Eclipse takes now 5 seconds as opposed to 30s on my old notebook), overall great experience. Then I started to build up my development stack, both as LAMP (using VirtualBox with a debian guest) and WAMP (windows native apache + mysql + php). I wanted to compare those two. This still all worked great out, then I started to pull in my projects to these stacks. And here came the nasty surprise, one of those projects produced a lot worse response times than on my old notebook (that was true for both the VirtualBox and WAMP stack). Apache, php and mysql configurations were practically identical in all environments. I started to do a lot of benchmarking and profiling, and here is what I've found: All general benchmarks (Performance Test 7.0, HDTune Pro, wPrime2 and some more) gave a big advantage to the new notebook. Nothing surprising here. Disc specific tests showed that read/write operations peaked around 380M/160M for the SSD, and all the different sized block operations also performed very well. Started apache performance benchmarking with Apache Benchmark for a small static html file (10 concurrent threads, 500 iterations). Old notebook: min 47ms, median 111ms, max 156ms New WAMP stack: min 71ms, median 135ms, max 296ms New LAMP stack (in VirtualBox): min 6ms, median 46ms, max 175ms Right here I don't get why the native WAMP stack performed so bad, but at least the LAMP environment brought the expected speed. Apache performance measurement for non-cached php content. The php runs a loop of 1000 and generates sha1(uniqid()) inisde. Again, 10 concurrent threads, 500 iterations were used for the benchmark. Old notebook: min 0ms, median 39ms, max 218ms New WAMP stack: min 20ms, median 61ms, max 186ms New LAMP stack (in VirtualBox): min 124ms, median 704ms, max 2463ms What the hell? The new LAMP performed miserably, and even the new native WAMP was outperformed by the old notebook. php + mysql test. The test consists of connecting to a database and reading a single record form a table using INNER JOIN on 3 more (indexed) tables, repeated 100 times within a loop. Databases were identical. 10 concurrent threads, 100 iterations were used for the benchmark. Old notebook: min 1201ms, median 1734ms, max 3728ms New WAMP stack: min 367ms, median 675ms, max 1893ms New LAMP stack (in VirtualBox): min 1410ms, median 3659ms, max 5045ms And the same test with concurrency set to 1 (instead of 10): Old notebook: min 1201ms, median 1261ms, max 1357ms New WAMP stack: min 399ms, median 483ms, max 539ms New LAMP stack (in VirtualBox): min 285ms, median 348ms, max 444ms Strictly for my purposes, as I'm using a self contained development environment (= low concurrency) I could be satisfied with the second test's result. Though I have no idea why the VirtualBox environment performed so bad with higher concurrency. Finally I performed a test of including many php files. The application that I mentioned at the beginning, the one that was performing so bad, has a heavy bootstrap, loads hundreds of small library and configuration files while initializing. So this test does nothing else just includes about 100 files. Concurrency set to 1, 100 iterations: Old notebook: min 140ms, median 168ms, max 406ms New WAMP stack: min 434ms, median 488ms, max 604ms New LAMP stack (in VirtualBox): min 413ms, median 1040ms, max 1921ms Even if I consider that VirtualBox reached those files via shared folders, and that slows things down a bit, I still don't see how could the old notebook outperform so heavily both new configurations. And I think this is the real root of the slow performance, as the application uses even more includes, and the whole bootstrap will occur several times within a page request (for each ajax call, for example). To sum it up, here I am with a brand new high-performance notebook that loads the same page in 20 seconds, that my old notebook can do in 5-7 seconds. Needless to say, I'm not a very happy person right now. Why do you think I experience these poor performance values? What are my options to remedy this situation?

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  • Centos 7. Freeradius fails to start on boot

    - by Alex
    I was messing around with FreeRADIUS and MySQL (MariaDB) and it seems FreeRADIUS service can't start properly on startup. But it starts fine using root user or in debug mode (radiusd -X) and works just fine! Debug mode shows no errors. systemctl command shows that radiusd.service has failed to start. /var/log/messages output: Aug 21 15:52:29 nexus-test systemd: Starting The Apache HTTP Server... Aug 21 15:52:29 nexus-test systemd: Starting MariaDB database server... Aug 21 15:52:29 nexus-test systemd: Starting FreeRADIUS high performance RADIUS server.... Aug 21 15:52:29 nexus-test systemd: Started OpenSSH server daemon. Aug 21 15:52:29 nexus-test mysqld_safe: 140821 15:52:29 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'. Aug 21 15:52:29 nexus-test mysqld_safe: 140821 15:52:29 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql Aug 21 15:52:30 nexus-test systemd: Started Postfix Mail Transport Agent. Aug 21 15:52:30 nexus-test avahi-daemon[604]: Registering new address record for fe80::250:56ff:fe85:e4af on eth0.*. Aug 21 15:52:30 nexus-test systemd: radiusd.service: control process exited, code=exited status=1 Aug 21 15:52:30 nexus-test systemd: Failed to start FreeRADIUS high performance RADIUS server.. Aug 21 15:52:30 nexus-test systemd: Unit radiusd.service entered failed state. Aug 21 15:52:31 nexus-test kdumpctl: kexec: loaded kdump kernel Aug 21 15:52:31 nexus-test kdumpctl: Starting kdump: [OK] Aug 21 15:52:31 nexus-test systemd: Started Crash recovery kernel arming. Aug 21 15:52:31 nexus-test systemd: Started The Apache HTTP Server. Aug 21 15:52:31 nexus-test systemd: Started MariaDB database server. /var/log/radius/radius.log output: Thu Aug 21 15:24:16 2014 : Info: rlm_sql (sql): Driver rlm_sql_mysql (module rlm_sql_mysql) loaded and linked Thu Aug 21 15:24:16 2014 : Info: rlm_sql (sql): Attempting to connect to database "radius" Thu Aug 21 15:24:16 2014 : Info: rlm_sql (sql): Opening additional connection (0) Thu Aug 21 15:24:16 2014 : Error: rlm_sql_mysql: Couldn't connect socket to MySQL server radius@localhost:radius Thu Aug 21 15:24:16 2014 : Error: rlm_sql_mysql: Mysql error 'Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)' Thu Aug 21 15:24:16 2014 : Error: rlm_sql (sql): Opening connection failed (0) Thu Aug 21 15:24:16 2014 : Error: /etc/raddb/mods-enabled/sql[47]: Instantiation failed for module "sql" After seeing this I tried to replicate the problem, killed mariadb.service and started to run debug mode again. And it spits out the same problem as in the radius.log. I tried disabling iptables and firewalld and rebooting, but no luck: systemctl disable iptables systemctl disable firewalld So maybe the problem is in the process startup order or delay of some kind. Maybe FreeRADIUS's SQL module can't connect to not yet started MariaDB? If it, how can I fix this? In earlier versions of RHEL/CENTOS I know you easily see service start order in like rc.d or stuff, now IDK. I am new to this fancy "systemd", "systemctl", "firewalld" stuff Centos 7 introduced so sorry I'm a little bit confused. Also this new FreeRADIUS 3 structure... PS. MariaDB is enabled on startup, credentials in FR DB configuration are correct A little update: cat /etc/systemd/system/multi-user.target.wants/radiusd.service output: [Unit] Description=FreeRADIUS high performance RADIUS server. After=syslog.target network.target [Service] Type=forking PIDFile=/var/run/radiusd/radiusd.pid ExecStartPre=-/bin/chown -R radiusd.radiusd /var/run/radiusd ExecStartPre=/usr/sbin/radiusd -C ExecStart=/usr/sbin/radiusd -d /etc/raddb ExecReload=/usr/sbin/radiusd -C ExecReload=/bin/kill -HUP $MAINPID [Install] WantedBy=multi-user.target

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  • LDAP object class violation: attribute ou not allowed in suffix?

    - by Paramaeleon
    I am about to set up a LDAP directory. It is used as a tool to communicate user permissions from a web application to WebDav file system access, e.g. adding a user to the web platform shall allow login to the file system with the same credentials. There are no other usages intended. Following this German tutorial which encourages the use of the attributes c, o, ou etc. over dc, I configured the following suffix and root: suffix "ou=webtool,o=myOrg,c=de" rootdn "cn=ldapadmin,ou=webtool,o=myOrg,c=de" Server starts and I can connect to it by LDAP Admin, which reports “LDAP error: Object lacks”. Well, there aren’t any objects yet. I now want to create the root and admin elements from shell. I created an init.ldif file: dn: ou=webtool,o=myOrg,c=de objectclass: dcObject objectclass: organization dc: webtool o: webtool dn: cn=ldapadmin,ou=webtool,o=myOrg,c=de objectclass: organizationalRole cn: ldapadmin Trying to load the file runs into an error, telling me that ou is not allowed: server:~ # ldapadd -x -D "cn=ldapadmin,ou=webtool,o=myOrg,c=de" -W -f init.ldif Enter LDAP Password: adding new entry "ou=webtool,o=myOrg,c=de" ldap_add: Object class violation (65) additional info: attribute 'ou' not allowed I am not using ou anywhere except in the suffix, so the question: Isn’t it allowed here? What is allowed here? Here is my answer. I am not allowed to post it as answer for 8 hours, so don’t mind that it is part of the question by now. I will move it outside some day, if I don’t forget to do so. There are numberous dependencies for the creation of elements, and error messages are rather confusing if you don’t know of the concept. The objectclass isn’t necessarily dcObject for the databases’ root node, as it is likely to guess when you read several tutoriales. Instead, it must correspond to the object’s type: Here, for a name starting with ou=, it must be organizationalUnit. I found this piece of information in these tables [Link removed due to restriction: Oops! Your edit couldn't be submitted because: We're sorry, but as a spam prevention mechanism, new users can only post a maximum of two hyperlinks. Earn more than 10 reputation to post more hyperlinks. Link is below]. Further on, the object class dictates which properties must and can be added in the record. Here, organizationalUnit must have an ou: entry and must not have neither dc: nor o: entry. The healthy init.ldif file looks like that: dn: ou=webtool,o=myOrg,c=de objectclass: organizationalUnit ou: LDAP server for my webtool dn: cn=ldapadmin,ou=webtool,o=myOrg,c=de objectclass: organizationalRole cn: ldapadmin Note: The page also states: “While many objectClasses show no MUST attributes you must (ouch) follow any hierarchy […] to determine if this is the really case.” I thought that would mean my root record would have to provide the must fields for c= and o= (c: and o:, respectively) but this isn’t the case. Link in answer is (1): http :// www (dot) zytrax (dot) com/books/ldap/ape/ "Appendix E: LDAP - Object Classes and Attributes"

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  • Server hung with "blocked for more than 120 seconds", diskless

    - by alterpub
    I have server which hung every 2-5 days. dmesg show following situation: kernel: [490894.231753] INFO: task munin-html:10187 blocked for more than 120 seconds. kernel: [490894.231799] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: [490894.231843] munin-html D 0000000000000000 0 10187 9796 0x00000000 kernel: [490894.231878] ffff88063174b968 0000000000000082 ffff88063174b8d8 0000000000015b80 kernel: [490894.231930] ffff88063174bfd8 0000000000015b80 ffff88063174bfd8 ffff88062fe644d0 kernel: [490894.231982] 0000000000015b80 0000000000015b80 ffff88063174bfd8 0000000000015b80 kernel: [490894.232033] Call Trace: kernel: [490894.232059] [<ffffffff8117fce0>] ? sync_buffer+0x0/0x50 kernel: [490894.232089] [<ffffffff815a1f13>] io_schedule+0x73/0xc0 kernel: [490894.232115] [<ffffffff8117fd25>] sync_buffer+0x45/0x50 kernel: [490894.232143] [<ffffffff815a258f>] __wait_on_bit+0x5f/0x90 kernel: [490894.232170] [<ffffffff8117fce0>] ? sync_buffer+0x0/0x50 kernel: [490894.232197] [<ffffffff815a2638>] out_of_line_wait_on_bit+0x78/0x90 kernel: [490894.232227] [<ffffffff81080250>] ? wake_bit_function+0x0/0x40 kernel: [490894.232255] [<ffffffff8117fcd6>] __wait_on_buffer+0x26/0x30 kernel: [490894.232288] [<ffffffffa00131be>] squashfs_read_data+0x1be/0x520 [squashfs] kernel: [490894.232320] [<ffffffff8114f0f1>] ? __mem_cgroup_try_charge+0x71/0x450 kernel: [490894.232350] [<ffffffffa0013963>] squashfs_cache_get+0x1c3/0x320 [squashfs] kernel: [490894.232381] [<ffffffffa00136eb>] ? squashfs_copy_data+0x10b/0x130 [squashfs] kernel: [490894.232426] [<ffffffff815a3dbe>] ? _raw_spin_lock+0xe/0x20 kernel: [490894.232454] [<ffffffffa0013b68>] ? squashfs_read_metadata+0x48/0xf0 [squashfs] kernel: [490894.232499] [<ffffffffa0013ae1>] squashfs_get_datablock+0x21/0x30 [squashfs] kernel: [490894.232544] [<ffffffffa0015026>] squashfs_readpage+0x436/0x4a0 [squashfs] kernel: [490894.232575] [<ffffffff8111a375>] ? __inc_zone_page_state+0x35/0x40 kernel: [490894.232606] [<ffffffff8110d072>] __do_page_cache_readahead+0x172/0x210 kernel: [490894.232636] [<ffffffff8110d131>] ra_submit+0x21/0x30 kernel: [490894.232662] [<ffffffff811045f3>] filemap_fault+0x3f3/0x450 kernel: [490894.232691] [<ffffffff812bd156>] ? prio_tree_insert+0x256/0x2b0 kernel: [490894.232726] [<ffffffffa009225d>] aufs_fault+0x11d/0x170 [aufs] kernel: [490894.232755] [<ffffffff8111f6d4>] __do_fault+0x54/0x560 kernel: [490894.232782] [<ffffffff81122f39>] handle_mm_fault+0x1b9/0x440 kernel: [490894.232811] [<ffffffff811286f5>] ? do_mmap_pgoff+0x335/0x380 kernel: [490894.232840] [<ffffffff815a7af5>] do_page_fault+0x125/0x350 kernel: [490894.232867] [<ffffffff815a4675>] page_fault+0x25/0x30 Os info cat /etc/issue.net Ubuntu 10.04.2 LTS uname -a Linux Shard1Host3 2.6.35-32-server #68~lucid1-Ubuntu SMP Wed Mar 28 18:33:00 UTC 2012 x86_64 GNU/Linux This system load via ltsp and hasn't harddrives also it has a lot of memory 24Gb. free -m total used free shared buffers cached Mem: 24152 17090 7061 0 50 494 -/+ buffers/cache: 16545 7607 Swap: 0 0 0 I put vmstat info here but I think it won't give results after reboot vmstat 1 30 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 7231156 52196 506400 0 0 0 0 172 143 7 0 92 0 1 0 0 7231024 52196 506400 0 0 0 0 7859 16233 5 0 94 0 0 0 0 7231024 52196 506400 0 0 0 0 7870 16446 2 0 98 0 0 0 0 7230900 52196 506400 0 0 0 0 7308 15661 5 0 95 0 0 0 0 7231100 52196 506400 0 0 0 0 7960 16543 6 0 94 0 0 0 0 7231100 52196 506400 0 0 0 0 7542 16047 5 1 94 0 3 0 0 7231100 52196 506400 0 0 0 0 7709 16621 3 0 96 0 0 0 0 7231220 52196 506400 0 0 0 0 7857 16552 4 0 96 0 0 0 0 7231220 52196 506400 0 0 0 0 7192 15491 6 0 94 0 0 0 0 7231220 52196 506400 0 0 0 0 7423 15792 5 1 94 0 1 0 0 7231260 52196 506404 0 0 0 0 7686 16296 2 0 98 0 0 0 0 7231260 52196 506404 0 0 0 0 6976 15183 5 0 95 0 0 0 0 7231260 52196 506404 0 0 0 0 7303 15600 4 0 95 0 0 0 0 7231320 52196 506404 0 0 0 0 7967 16241 1 0 98 0 0 0 0 7231444 52196 506404 0 0 0 0 6948 15113 6 0 94 0 0 0 0 7231444 52196 506404 0 0 0 0 7931 16181 6 0 94 0 1 0 0 7231516 52196 506404 0 0 0 0 7715 15829 6 0 94 0 0 0 0 7231516 52196 506404 0 0 0 0 7771 16036 2 0 97 0 0 0 0 7231268 52196 506404 0 0 0 0 7782 16202 6 0 94 0 1 0 0 7231212 52196 506404 0 0 0 0 7457 15622 4 0 96 0 0 0 0 7231212 52196 506404 0 0 0 0 7573 16045 2 0 98 0 2 0 0 7231216 52196 506404 0 0 0 0 7689 16076 6 0 94 0 0 0 0 7231424 52196 506404 0 0 0 0 7429 15650 4 0 95 0 3 0 0 7231424 52196 506404 0 0 0 0 7534 16168 3 0 97 0 1 0 0 7230548 52196 506404 0 0 0 0 8559 15926 7 1 92 0 0 0 0 7230672 52196 506404 0 0 0 0 7720 15905 2 0 98 0 0 0 0 7230548 52196 506404 0 0 0 0 7677 16313 5 0 95 0 1 0 0 7230676 52196 506404 0 0 0 0 7209 15432 5 0 95 0 0 0 0 7230800 52196 506404 0 0 0 0 7522 15861 2 0 98 0 0 0 0 7230552 52196 506404 0 0 0 0 7760 16661 5 0 95 0 In the munin(monitoring system) graphs I see(before server hung): Disk(nbd0) IOs per device: read: 289m but avg by week 2.09m Disk(nbd0) throughput per device: read: 4.73k but avg by week 108.76 Disk(nbd0) utilization per device: 100% but avg by week 1.2% Eth0 traffic was low: in/out only 2Mbps Number of threads increased to 566 usually 392 Fork rate 1.08 but usually 2.82 VMStat(processes state) Increased to 17.77(from 0 as far as I could see in the graph) CPU usage iowait 880.46% when usually 6.67% It'll be great if somebody help me to understand what's up.

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  • VMware vSphere cluster design for site redundancy

    - by Stefan Radovanovici
    I have a question about the best design for site redudancy when using vSphere clusters. A bit of background info about our situation first though. We are a medium-sized company with two main offices, located in different countries. Our networks are linked by a Layer2 150Mbps leased line which is currently underused. We have a variety of services running for internal use within the company, some on physycal servers and some on existing vSphere clusters. In our department we also run several services (almost all running under various forms of Linux) like NTP, Syslog, jump servers, monitoring servers and so on. We have now the requirement that those servers need to be redundant within each location (which they are not at the moment) and also site redudant (which they are to some extent, the servers are duplicated in the 2nd location with configurations kept in sync via various methods at the application layer). There is no SAN available for us, at least not something that we can use at the moment. Cost is also an issue. While we do have some budget available for this, we can't afford to buy SANs for both locations for example. I looked at the VSA feature and it seems that this could be something for us but I am unsure how to solve the site-redudancy requirement. At the moment for testing purposes I am setting up in a lab a vSphere 5 with VSA on two ESXi hosts. I am currently using the Essentials Plus kit with VSA license, which allows me to build a VSA cluster on up to 3 hosts, together with a vCenter license to manage them. The hosts each have two dual-port network cards and two 600GB drives, running in Raid1. Hardware-wise this will be enough for us to run the all the services we need as VMs and will provide redundandcy within the site. At the moment I see only two option to have site redundancy: build an identical VSA cluter in the second location and keep the various services sync'ed at application layer (database sync, rsync and so on). simply move one of the hosts from the existing cluster to the second location, basically having the VSA cluster span the 150Mbps link between the sites. I would very much prefer the second option but I am unsure how well it'll work, if it can work at all. Technically it should, we can span the needed VLANs across the leased line and have them available in the second location. The advantage would be that we don't need to worry at all about sync'ing databases and the like. But I have the feeling that the bandwidth will not be enough, I have no way of knowing how much traffic will the VSA cluster generate between the hosts. I realize that this will most likely depend on the individual usage of the VMs but still, I have no idea how VSA replicates data between the ESXi hosts. Are these my only options or can my goals be achieved in some other way ? Is there perhaps a way to have some sort of "cold stand by" cluster in the second location where the VMs would be sync'ed once per night from the main location ? The idea is that in case the first site becomes unavailable, we would be able to bring all those VMs online there. We would be ok with the data being 1 day old. Any answers are appreciated. Best regards, Stefan

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  • How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?

    - by Stu Thompson
    Prelude: I'm a code-monkey that's increasingly taken on SysAdmin duties for my small company. My code is our product, and increasingly we provide the same app as SaaS. About 18 months ago I moved our servers from a premium hosting centric vendor to a barebones rack pusher in a tier IV data center. (Literally across the street.) This ment doing much more ourselves--things like networking, storage and monitoring. As part the big move, to replace our leased direct attached storage from the hosting company, I built a 9TB two-node NAS based on SuperMicro chassises, 3ware RAID cards, Ubuntu 10.04, two dozen SATA disks, DRBD and . It's all lovingly documented in three blog posts: Building up & testing a new 9TB SATA RAID10 NFSv4 NAS: Part I, Part II and Part III. We also setup a Cacit monitoring system. Recently we've been adding more and more data points, like SMART values. I could not have done all this without the awesome boffins at ServerFault. It's been a fun and educational experience. My boss is happy (we saved bucket loads of $$$), our customers are happy (storage costs are down), I'm happy (fun, fun, fun). Until yesterday. Outage & Recovery: Some time after lunch we started getting reports of sluggish performance from our application, an on-demand streaming media CMS. About the same time our Cacti monitoring system sent a blizzard of emails. One of the more telling alerts was a graph of iostat await. Performance became so degraded that Pingdom began sending "server down" notifications. The overall load was moderate, there was not traffic spike. After logging onto the application servers, NFS clients of the NAS, I confirmed that just about everything was experiencing highly intermittent and insanely long IO wait times. And once I hopped onto the primary NAS node itself, the same delays were evident when trying to navigate the problem array's file system. Time to fail over, that went well. Within 20 minuts everything was confirmed to be back up and running perfectly. Post-Mortem: After any and all system failures I perform a post-mortem to determine the cause of the failure. First thing I did was ssh back into the box and start reviewing logs. It was offline, completely. Time for a trip to the data center. Hardware reset, backup an and running. In /var/syslog I found this scary looking entry: Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_00], 6 Currently unreadable (pending) sectors Nov 15 06:49:44 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_07], SMART Prefailure Attribute: 1 Raw_Read_Error_Rate changed from 171 to 170 Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 16 Currently unreadable (pending) sectors Nov 15 06:49:45 umbilo smartd[2827]: Device: /dev/twa0 [3ware_disk_10], 4 Offline uncorrectable sectors Nov 15 06:49:45 umbilo smartd[2827]: Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error Nov 15 06:49:45 umbilo smartd[2827]: # 1 Short offline Completed: read failure 90% 6576 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 2 Short offline Completed: read failure 90% 6087 3421766910 Nov 15 06:49:45 umbilo smartd[2827]: # 3 Short offline Completed: read failure 10% 5901 656821791 Nov 15 06:49:45 umbilo smartd[2827]: # 4 Short offline Completed: read failure 90% 5818 651637856 Nov 15 06:49:45 umbilo smartd[2827]: So I went to check the Cacti graphs for the disks in the array. Here we see that, yes, disk 7 is slipping away just like syslog says it is. But we also see that disk 8's SMART Read Erros are fluctuating. There are no messages about disk 8 in syslog. More interesting is that the fluctuating values for disk 8 directly correlate to the high IO wait times! My interpretation is that: Disk 8 is experiencing an odd hardware fault that results in intermittent long operation times. Somehow this fault condition on the disk is locking up the entire array Maybe there is a more accurate or correct description, but the net result has been that the one disk is impacting the performance of the whole array. The Question(s) How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt? Am I being naïve to think that the RAID card should have dealt with this? How can I prevent a single misbehaving disk from impacting the entire array? Am I missing something?

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  • Network update solutions for a company of ~20 (5 local, 15 remote)?

    - by Margaret
    Hi all This is probably going to be a bit up in the air, because we're still in the "reaching towards solutions" phase, but I figured I'd see what you guys had to say. Plus I honestly know very little about systems and what is good and bad pratice. My organisation has always more or less worked on the concept of local machines; since it primarily employed contractors who were working from home, each of those people was largely responsible for their own machine and backup procedures and the like. We're now expanding, though we're still reasonably small (we're up to about 20 staff members). Most people still work remotely, but we have a central office where about five people are working. But we're getting large enough that we're starting to think it would be a good idea to have a central file server, and things like that - if someone gets hit by a bus, we want someone else to know where to look for the files to continue their work. A lot of the people who work for us remotely work on projects for other companies as well, so I don't want to force them to log in to our server whenever they're on a network. But I do want to make connection to be as painless as possible to do so, to improve utilisation. The other thing is that we're getting more people who would like to remote into the office server and do their work there. Our current remote connection application is an SSH install that allows people access to the network; the problem is, it's a black box to me, and I've never understood how to even connect to it (despite supposedly being de facto sysadmin). Thus far I've been able to bounce questions about how to get it working to the guy who does know it well, but he's leaving the company soon. So we probably need a solution for this that I actually understand. We were knocking around the idea of implementing a VPN with some form of remote desktop, and someone mentioned that this was largely a matter of purchasing a router capable of it; I'm not sure of the truth of that statement. This is what we have in the office: Two shiny new i7 servers, each running Windows Server 2008. Precise eventual layout is still being debated, a little, but the current suggestion is that one is primary database crunching, while the other is a warm backup of the databases, along with running Reporting Services. They currently have SQL Server 2008 installed on them, which is being connected to via the 'sa' account. We're hoping to make each person use their own account (preferably one tied to the 'central' password we set up, so we can use Windows Authentication). An older server, running XP Pro, that we are currently using as a test bed for a project that requires access to older versions of software. This machine is also being used to take backups, but I'm thinking of moving that functionality elsewhere. A spare desktop from a guy who left the company (XP Pro). We're thinking of bumping up the hard disk space and using it as the magical file server that's going to solve one particular everything. Assorted desktops, laptops, etc, at least one for each person in the office (mix of Win XP and Win 7; occasionally a person who normally works remotely might drop in to the office and bring a laptop bearing Vista, but it's pretty rare). All are set up as local user accounts at the moment; I don't know if it's the best arrangement. Purchasing more hardware is not a big problem, but we figure we might as well make use of what we've got first. Is Active Directory a big magic wand that's going to solve all the world's problems? Is there some other arrangement we should be looking to instead?

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  • How does the Cloud compare to Colocation? And development too

    - by David
    Currently I/we run a SaaS web application where each subscriber has their own physical instance of the application in addition to their own database. The setup has each web application instance deployed on two different IIS boxes both for load-balancing and redundancy (the machines have their Windows Update install times 12 hours apart, for example). Databases are mirrored on two different SQL Server 2012 machines with AlwaysOn for uptime. I don't make use of SQL Server clustering (as it doesn't provide storage-level failover: we don't have a shared storage box). Because it's a Windows setup it means there are two Domain Controllers (we cheat: they're both Mac Minis, 17W each, which keeps our colo power costs low). Finally there's also an Exchange server (Mailbox, Hub Transport and Client Access). One of the SQL Servers also doubles-up as an Exchange Hub Transport. Running costs are about $700 a month for our quarter-rack colocation (which includes power and peering/transfer), then there's about $150 a month for SPLA licensing, so $850 a month in total. Then there's the hard-to-quantify cost of administration, but I reckon I spend a couple of hours a week checking-in on the servers: reviewing event logs, etc. I keep getting bombarded by ads and manufactured news stories about how great "the cloud" is. Back in 2008 when the cloud was taking off I was reading up about the proper "cloud" services like Google AppEngine, where you write in Python against Google's API and that's how they scale your application across servers and also use their database provider for scaling storage. Simple enough to understand. Then came along Amazon, and I understand how Amazon Storage works, but I'm not sure how Amazon Compute works: web application pages don't take much CPU time to compute, how do you even quantify usage anyway? Finally, RackSpace gets in the act and now I'm really confused. RackSpace advertise "Cloud" SQL Server 2012 available for about "$0.70 per hour", going by how they advertise it I thought the "hour" meant the sum of CPU time, IO blocking time, maybe time spent transferring data, so for a low-intensity application that works out pretty cheap then? Nope. I went on to a Sales Chat window and spoke to one of their advisors. They told me the $0.70/hour was actually for every hour the SQL Server is running... but who wants a SQL Server for only a few hours? You're going to need it available 24 hours a day for months on end. $0.70 * 24 * 31 works out at $520 a month, which is rediculously expensive for SQL Server. An SPLA license for SQL Server is only $50 a month or so. That $520 a month does not include "fanatical support", and you also need to stack on top the costs of the host Windows server instance too. From what I can tell, Rackspace's "Cloud" products seem like like an cynical rebranding of an overpriced VPS service, but priced by the hour. I have the same confusion about Windows Azure which uses similar terms to describe the products available, but I think that's because Azure offers both traditional shared webhosting in addition to their own APIs you can target for scalable applications.

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