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  • Alternatives to Pessimistic Locking in Cluster Applications

    - by amphibient
    I am researching alternatives to database-level pessimistic locking to achieve transaction isolation in a cluster of Java applications going against the same database. Synchronizing concurrent access in the application tier is clearly not a solution in the present configuration because the same database transaction can be invoked from multiple JVMs concurrently. Currently, we are subject to occasional race conditions which, due to the optimistic locking we have in place via Hibernate, cause a StaleObjectStateException exception and data loss. I have a moderately large transaction within the scope of my refactoring project. Let's describe it as updating one top-level table row and then making various related inserts and/or updates to several of its child entities. I would like to insure exclusive access to the top-level table row and all of the children to be affected but I would like to stay away from pessimistic locking at the database level for performance reasons mostly. We use Hibernate for ORM. Does it make sense to start a single (perhaps synchronous) message queue application into which this method could be moved to insure synchronized access as opposed to each cluster node using its own, which is a clear race condition hazard? I am mentioning this approach even though I am not confident in it because both the top-level table row and its children could also be updated from other system calls, not just the mentioned transaction. So I am seeking to design a solution where the top-level table row and its children will all somehow be pseudo-locked (exclusive transaction isolation) but at the application and not the database level. I am open to ideas and suggestions, I understand this is not a very cut and dried challenge.

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  • Windows Azure Learning Plan - Security

    - by BuckWoody
    This is one in a series of posts on a Windows Azure Learning Plan. You can find the main post here. This one deals with Security for  Windows Azure.   General Security Information Overview and general  information about Windows Azure Security - what it is, how it works, and where you can learn more. General Security Whitepaper – answers most questions http://blogs.msdn.com/b/usisvde/archive/2010/08/10/security-white-paper-on-windows-azure-answers-many-faq.aspx Windows Azure Security Notes from the Patterns and Practices site http://blogs.msdn.com/b/jmeier/archive/2010/08/03/now-available-azure-security-notes-pdf.aspx Overview of Azure Security http://www.windowsecurity.com/articles/Microsoft-Azure-Security-Cloud.html Azure Security Resources http://reddevnews.com/articles/2010/08/19/microsoft-releases-windows-azure-security-resources.aspx Cloud Computing Security Considerations http://www.microsoft.com/downloads/en/details.aspx?FamilyID=68fedf9c-1c27-4642-aa5b-0a34472303ea&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+MicrosoftDownloadCenter+%28Microsoft+Download+Center Security in Cloud Computing – a Microsoft Perspective http://www.microsoft.com/downloads/en/details.aspx?FamilyID=7c8507e8-50ca-4693-aa5a-34b7c24f4579&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+MicrosoftDownloadCenter+%28Microsoft+Download+Center Physical Security for Microsoft’s Online Computing Information on the Infrastructure and Locations for Azure Physical Security. The Global Foundation Services Group at Microsoft handles physical security http://www.globalfoundationservices.com/security/index.html Microsoft’s Security Response Center http://www.microsoft.com/security/msrc/ Software Security for Microsoft’s Online Computing Steps we take as a company to develop secure software Windows Azure is developed using the Trustworthy Computing Initiative http://www.microsoft.com/about/twc/en/us/default.aspx and  http://msdn.microsoft.com/en-us/library/ms995349.aspx Identity and Access in the Cloud http://blogs.msdn.com/b/technology_titbits_by_rajesh_makhija/archive/2010/10/29/identity-and-access-in-the-cloud.aspx Security Steps you should take While Microsoft takes great pains to secure the infrastructure, platform and code for Windows Azure, you have a responsibility to write secure code. These pointers can help you do that. Securing your cloud architecture, step-by-step http://technet.microsoft.com/en-us/magazine/gg296364.aspx Security Guidelines for Windows Azure http://redmondmag.com/articles/2010/06/15/microsoft-issues-security-guidelines-for-windows-azure.aspx  Best Practices for Windows Azure Security http://blogs.msdn.com/b/vbertocci/archive/2010/06/14/security-best-practices-for-developing-windows-azure-applications.aspx Active Directory and Windows Azure http://blogs.msdn.com/b/plankytronixx/archive/2010/10/22/projecting-your-active-directory-identity-to-the-azure-cloud.aspx Understanding Encryption (great overview and tutorial) http://blogs.msdn.com/b/plankytronixx/archive/2010/10/23/crypto-primer-understanding-encryption-public-private-key-signatures-and-certificates.aspx Securing your Connection Strings (SQL Azure) http://blogs.msdn.com/b/sqlazure/archive/2010/09/07/10058942.aspx Getting started with Windows Identity Foundation (WIF) quickly http://blogs.msdn.com/b/alikl/archive/2010/10/26/windows-identity-foundation-wif-fast-track.aspx

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  • Computing a normal matrix in conjunction with gluLookAt

    - by Chris Smith
    I have a hand-rolled camera class that converts yaw, pitch, and roll angles into a forward, side, and up vector suitable for calling gluLookAt. Using this camera class I can modify the model-view matrix to move about the 3D world just fine. However, I am having trouble when using this camera class (and associated model-view matrix) when trying to perform directional lighting in my vertex shader. The problem is that the light direction, (0, 1, 0) for example, is relative to where the 'camera is looking' and not the actual world coordinates. (Or is this eye coordinates vs. model coordinates?) I would like the light direction to be unaffected by the camera's viewing direction. For example, when the camera is looking down the Z axis the ground is lit correctly. However, if I point the camera straight at the ground, then it goes dark. This is (I think) because the light direction is parallel with the camera's 'up' vector which is perpendicular with the ground's normal vector. I tried computing the normal matrix without taking the camera's model view into account, but then none of my objects were rotated correctly. Sorry if this sounds vague. I suspect there is a straight forward answer, but I'm not 100% clear on how the normal matrix should be used for transforming vertex normals in my vertex shader. For reference, here is pseudo code for my rendering loop: pMatrix = new Matrix(); pMatrix = makePerspective(...) mvMatrix = new Matrix() camera.apply(mvMatrix); // Calls gluLookAt // Move the object into position. mvMatrix.translatev(position); mvMatrix.rotatef(rotation.x, 1, 0, 0); mvMatrix.rotatef(rotation.y, 0, 1, 0); mvMatrix.rotatef(rotation.z, 0, 0, 1); var nMatrix = new Matrix(); nMatrix.set(mvMatrix.get().getInverse().getTranspose()); // Set vertex shader uniforms. gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, new Float32Array(pMatrix.getFlattened())); gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, new Float32Array(mvMatrix.getFlattened())); gl.uniformMatrix4fv(shaderProgram.nMatrixUniform, false, new Float32Array(nMatrix.getFlattened())); // ... gl.drawElements(gl.TRIANGLES, this.vertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0); And the corresponding vertex shader: // Attributes attribute vec3 aVertexPosition; attribute vec4 aVertexColor; attribute vec3 aVertexNormal; // Uniforms uniform mat4 uMVMatrix; uniform mat4 uNMatrix; uniform mat4 uPMatrix; // Varyings varying vec4 vColor; // Constants const vec3 LIGHT_DIRECTION = vec3(0, 1, 0); // Opposite direction of photons. const vec4 AMBIENT_COLOR = vec4 (0.2, 0.2, 0.2, 1.0); float ComputeLighting() { vec4 transformedNormal = vec4(aVertexNormal.xyz, 1.0); transformedNormal = uNMatrix * transformedNormal; float base = dot(normalize(transformedNormal.xyz), normalize(LIGHT_DIRECTION)); return max(base, 0.0); } void main(void) { gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0); float lightWeight = ComputeLighting(); vColor = vec4(aVertexColor.xyz * lightWeight, 1.0) + AMBIENT_COLOR; } Note that I am using WebGL, so if the anser is use glFixThisProblem(...) any pointers on how to re-implement that on WebGL if missing would be appreciated.

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  • Your thoughts on Best Practices for Scientific Computing?

    - by John Smith
    A recent paper by Wilson et al (2014) pointed out 24 Best Practices for scientific programming. It's worth to have a look. I would like to hear opinions about these points from experienced programmers in scientific data analysis. Do you think these advices are helpful and practical? Or are they good only in an ideal world? Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, Haddock SHD, Huff KD, Mitchell IM, Plumbley MD, Waugh B, White EP, Wilson P (2014) Best Practices for Scientific Computing. PLoS Biol 12:e1001745. http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001745 Box 1. Summary of Best Practices Write programs for people, not computers. (a) A program should not require its readers to hold more than a handful of facts in memory at once. (b) Make names consistent, distinctive, and meaningful. (c) Make code style and formatting consistent. Let the computer do the work. (a) Make the computer repeat tasks. (b) Save recent commands in a file for re-use. (c) Use a build tool to automate workflows. Make incremental changes. (a) Work in small steps with frequent feedback and course correction. (b) Use a version control system. (c) Put everything that has been created manually in version control. Don’t repeat yourself (or others). (a) Every piece of data must have a single authoritative representation in the system. (b) Modularize code rather than copying and pasting. (c) Re-use code instead of rewriting it. Plan for mistakes. (a) Add assertions to programs to check their operation. (b) Use an off-the-shelf unit testing library. (c) Turn bugs into test cases. (d) Use a symbolic debugger. Optimize software only after it works correctly. (a) Use a profiler to identify bottlenecks. (b) Write code in the highest-level language possible. Document design and purpose, not mechanics. (a) Document interfaces and reasons, not implementations. (b) Refactor code in preference to explaining how it works. (c) Embed the documentation for a piece of software in that software. Collaborate. (a) Use pre-merge code reviews. (b) Use pair programming when bringing someone new up to speed and when tackling particularly tricky problems. (c) Use an issue tracking tool. I'm relatively new to serious programming for scientific data analysis. When I tried to write code for pilot analyses of some of my data last year, I encountered tremendous amount of bugs both in my code and data. Bugs and errors had been around me all the time, but this time it was somewhat overwhelming. I managed to crunch the numbers at last, but I thought I couldn't put up with this mess any longer. Some actions must be taken. Without a sophisticated guide like the article above, I started to adopt "defensive style" of programming since then. A book titled "The Art of Readable Code" helped me a lot. I deployed meticulous input validations or assertions for every function, renamed a lot of variables and functions for better readability, and extracted many subroutines as reusable functions. Recently, I introduced Git and SourceTree for version control. At the moment, because my co-workers are much more reluctant about these issues, the collaboration practices (8a,b,c) have not been introduced. Actually, as the authors admitted, because all of these practices take some amount of time and effort to introduce, it may be generally hard to persuade your reluctant collaborators to comply them. I think I'm asking your opinions because I still suffer from many bugs despite all my effort on many of these practices. Bug fix may be, or should be, faster than before, but I couldn't really measure the improvement. Moreover, much of my time has been invested on defence, meaning that I haven't actually done much data analysis (offence) these days. Where is the point I should stop at in terms of productivity? I've already deployed: 1a,b,c, 2a, 3a,b,c, 4b,c, 5a,d, 6a,b, 7a,7b I'm about to have a go at: 5b,c Not yet: 2b,c, 4a, 7c, 8a,b,c (I could not really see the advantage of using GNU make (2c) for my purpose. Could anyone tell me how it helps my work with MATLAB?)

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  • Cloud computing over Client-server: differences, cons and pros ?

    - by Vimvq1987
    As far as I know, Cloud computing might be a evolution in software architect, and it will replace some current architectures, such as client-server. These two architecture seem to share similarities for me (I know very little about both), but I don't know the differences between them. What are the cons and pros of cloud computing over client-server architecture? Thank you so much.

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  • What Parallel computing APIs take good use of sockets?

    - by Ole Jak
    What Parallel computing APIs take good use of sockets? So my programm uses soskets, what Parallel computing APIs I can use that would help me but will not obligate me to go from sockets to anything else... I mean when we are on claster with some special, not socket infrastructure sistem that API emulates something like socket but uses that infrustructure (so programm peforms much faster then on sockets, but keeps having nice soskets API)

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  • SLES 11 - ocfs2 - Locking does not appear to work

    - by Autobyte
    Hi I have two SLES 11 servers that are SAN attached to a Clarion CX-340. The SAN partition has been formatted with ocfs2 and I have both machines setup in a cluster and the cluster is running (all appears to be normal). I have a small java application as a locking test and when I run the application on both machines at the same time, I should get the lock on one server and the other should refuse the lock since the first already holds a lock on that file but in this case both servers get a lock on the same file. Basically my cluster.conf looks like this: node: ip_port = 7777 ip_address = 192.168.10.121 number = 1 name = osrsles10node1 cluster = osrsles10 node: ip_port = 7777 ip_address = 192.168.10.122 number = 2 name = osrsles10node2 cluster = osrsles10 cluster: node_count = 2 name = osrsles10 Please ask for any other info - I really need these locks to be exclusive to each server. Thanks.

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  • Good ways to restart all the computers in a remote cluster?

    - by vgm64
    I have a cluster that I manage and from time to time I get emails from each node (and head node) begging to be restarted after an automatic upgrade. Currently, my best solution so far is a shell script like: $> cat cluster_reboot.sh ssh [email protected] reboot ssh [email protected] reboot ssh [email protected] reboot ssh [email protected] reboot ssh [email protected] reboot ssh [email protected] reboot I end up just typing the root password six times, but it works, I guess. Is there a better way? Can I force the head node to reboot the computers for me?

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  • Do I need to buy Mysql cluster enterprise edition?

    - by Arman
    Hello, we have a ms-sql 2008 standard edition. The db became too huge, about 8 10^9 records.the db files are about 4.5tb each. We cannot effort us to get enterprise edition to slice the database. We need partitioning. So the idea is to use Mysql cluster with many datanodes. We already started to move data. I wondered do we need to buy a licens for mysqlcluster?are there performance difference between community edition and commercial one? Thanks Arman.

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  • How do I network this Windows Failover Cluster and MongoDB Replica Set? (diagram inside)

    - by arex1337
    As you can see, my two Windows Server Failover Cluster (WSFC) nodes have three network interfaces each, which connects them to three different networks : A public network A private network consisting of the WSFC nodes A private network consisting of the WSFC nodes and a machine with the WSFC Quorum Witness File Share Does this network configuration I've planned, make sense? Do I have the "right" number of NICs and networks? I'm thinking the 2nd NIC/network may be unnecessary. My two MongoDB Replica Set nodes also have three network interfaces each - very similar to the previous situation: A public network A private network consisting of the primary and secondary MongoDB Replica Set nodes A private network consisting of the primary, secondary and arbiter MongoDB Replica Set nodes Does this network configuration, make sense? Do I have the "right" number of NICs and networks? I'm thinking the 2nd NIC/network may be unnecessary. Here is the simpler version I'm considering: UPDATE:

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  • How to manage several Linux workstation like a cluster?

    - by Richard Zak
    How does one go about managing a lab of Linux workstations? I'd like for users to be able to log in, run their GUI apps (LibreOffice, Firefox, Eclipse, etc), and for the computers to be able to be used as compute nodes (OpenMPI). This part I'm fine with. But how can I centrally deploy a new software package or upgrade an installed package? How can I reload the entire OS on a given node, as if these workstations were part of a super computing cluster? Is there a nice program to help with setting up PXE booting and image management, and remotely managing packages? Ideally such a system would work with Ubuntu. If there isn't a nice package, how could this be set up manually?

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  • What is and what is not replicated in a glassfish cluster with a mod_jk load balancer?

    - by Navigateur
    I have a Glassfish (3.1.2) cluster over 2 computers as nodes, with a mod_jk load balancer. Are servlet instance variables replicated perfectly? If not, how do I make sure it is? Are all actions, including method calls and disk writes, replicated perfectly? If not, how do I make sure they are? These may seem like stupid questions, but I'm not seeking "load balancing" as much as I am seeking exact replication to enable future upgrading without any service interruption. How do I achieve this if it is not already the case?

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  • Clustered Graphs Visualization Techniques

    - by jameszhao00
    I need to visualize a relatively large graph (6K nodes, 8K edges) that has the following properties: Distinct Clusters. Approximately 50-100 Nodes per cluster and moderate interconnectivity at the cluster level Minimal (5-10 inter-cluster edges per cluster) interconnectivity between clusters Let global edge overlap = The edge overlaps caused by directly visualizing a graph of Clusters = {A, B, C, D, E}, Edges = {Pentagram of those clusters, which is non-planar by the way and will definitely generate edge overlap if you draw it out directly} Let Local Edge Overlap = the above but { A, B, C, D, E } are just nodes. I need to visualize graphs with the above in a way that satisfies the following requirements No global edge overlap (i.e. edge overlaps caused by inter-cluster properties is not okay) Local edge overlap within a cluster is fine Anyone have thoughts on how to best visualize a graph with the requirements above? One solution I've come up with to deal with the global edge overlap is to make sure a cluster A can only have a max of 1 direct edge to another cluster (B) during visualization. Any additional inter-cluster edges between cluster A - C, A - D, ... are disconnected and additional node/edges A - A_C, C - C_A, A - A_D, D - D_A... are created. Anyone have any thoughts?

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  • The Proper Use of the VM Role in Windows Azure

    - by BuckWoody
    At the Professional Developer’s Conference (PDC) in 2010 we announced an addition to the Computational Roles in Windows Azure, called the VM Role. This new feature allows a great deal of control over the applications you write, but some have confused it with our full infrastructure offering in Windows Hyper-V. There is a proper architecture pattern for both of them. Virtualization Virtualization is the process of taking all of the hardware of a physical computer and replicating it in software alone. This means that a single computer can “host” or run several “virtual” computers. These virtual computers can run anywhere - including at a vendor’s location. Some companies refer to this as Cloud Computing since the hardware is operated and maintained elsewhere. IaaS The more detailed definition of this type of computing is called Infrastructure as a Service (Iaas) since it removes the need for you to maintain hardware at your organization. The operating system, drivers, and all the other software required to run an application are still under your control and your responsibility to license, patch, and scale. Microsoft has an offering in this space called Hyper-V, that runs on the Windows operating system. Combined with a hardware hosting vendor and the System Center software to create and deploy Virtual Machines (a process referred to as provisioning), you can create a Cloud environment with full control over all aspects of the machine, including multiple operating systems if you like. Hosting machines and provisioning them at your own buildings is sometimes called a Private Cloud, and hosting them somewhere else is often called a Public Cloud. State-ful and Stateless Programming This paradigm does not create a new, scalable way of computing. It simply moves the hardware away. The reason is that when you limit the Cloud efforts to a Virtual Machine, you are in effect limiting the computing resources to what that single system can provide. This is because much of the software developed in this environment maintains “state” - and that requires a little explanation. “State-ful programming” means that all parts of the computing environment stay connected to each other throughout a compute cycle. The system expects the memory, CPU, storage and network to remain in the same state from the beginning of the process to the end. You can think of this as a telephone conversation - you expect that the other person picks up the phone, listens to you, and talks back all in a single unit of time. In “Stateless” computing the system is designed to allow the different parts of the code to run independently of each other. You can think of this like an e-mail exchange. You compose an e-mail from your system (it has the state when you’re doing that) and then you walk away for a bit to make some coffee. A few minutes later you click the “send” button (the network has the state) and you go to a meeting. The server receives the message and stores it on a mail program’s database (the mail server has the state now) and continues working on other mail. Finally, the other party logs on to their mail client and reads the mail (the other user has the state) and responds to it and so on. These events might be separated by milliseconds or even days, but the system continues to operate. The entire process doesn’t maintain the state, each component does. This is the exact concept behind coding for Windows Azure. The stateless programming model allows amazing rates of scale, since the message (think of the e-mail) can be broken apart by multiple programs and worked on in parallel (like when the e-mail goes to hundreds of users), and only the order of re-assembling the work is important to consider. For the exact same reason, if the system makes copies of those running programs as Windows Azure does, you have built-in redundancy and recovery. It’s just built into the design. The Difference Between Infrastructure Designs and Platform Designs When you simply take a physical server running software and virtualize it either privately or publicly, you haven’t done anything to allow the code to scale or have recovery. That all has to be handled by adding more code and more Virtual Machines that have a slight lag in maintaining the running state of the system. Add more machines and you get more lag, so the scale is limited. This is the primary limitation with IaaS. It’s also not as easy to deploy these VM’s, and more importantly, you’re often charged on a longer basis to remove them. your agility in IaaS is more limited. Windows Azure is a Platform - meaning that you get objects you can code against. The code you write runs on multiple nodes with multiple copies, and it all works because of the magic of Stateless programming. you don’t worry, or even care, about what is running underneath. It could be Windows (and it is in fact a type of Windows Server), Linux, or anything else - but that' isn’t what you want to manage, monitor, maintain or license. You don’t want to deploy an operating system - you want to deploy an application. You want your code to run, and you don’t care how it does that. Another benefit to PaaS is that you can ask for hundreds or thousands of new nodes of computing power - there’s no provisioning, it just happens. And you can stop using them quicker - and the base code for your application does not have to change to make this happen. Windows Azure Roles and Their Use If you need your code to have a user interface, in Visual Studio you add a Web Role to your project, and if the code needs to do work that doesn’t involve a user interface you can add a Worker Role. They are just containers that act a certain way. I’ll provide more detail on those later. Note: That’s a general description, so it’s not entirely accurate, but it’s accurate enough for this discussion. So now we’re back to that VM Role. Because of the name, some have mistakenly thought that you can take a Virtual Machine running, say Linux, and deploy it to Windows Azure using this Role. But you can’t. That’s not what it is designed for at all. If you do need that kind of deployment, you should look into Hyper-V and System Center to create the Private or Public Infrastructure as a Service. What the VM Role is actually designed to do is to allow you to have a great deal of control over the system where your code will run. Let’s take an example. You’ve heard about Windows Azure, and Platform programming. You’re convinced it’s the right way to code. But you have a lot of things you’ve written in another way at your company. Re-writing all of your code to take advantage of Windows Azure will take a long time. Or perhaps you have a certain version of Apache Web Server that you need for your code to work. In both cases, you think you can (or already have) code the the software to be “Stateless”, you just need more control over the place where the code runs. That’s the place where a VM Role makes sense. Recap Virtualizing servers alone has limitations of scale, availability and recovery. Microsoft’s offering in this area is Hyper-V and System Center, not the VM Role. The VM Role is still used for running Stateless code, just like the Web and Worker Roles, with the exception that it allows you more control over the environment of where that code runs.

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  • Setting up MySQL Cluster 7.0 in Linux

    <b>Linux Admin Zone:</b> "You might know that beginning with MySQL 5.1.24, support for the NDBCLUSTER storage engine was removed from the standard MySQL server binaries built by MySQL. Therefore, here I&#8217;m using MySQL Cluster edition instead of MySQL Community edition."

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  • SQL Server 2012 AlwaysOn: Multisite Failover Cluster Instance

    SQL Server Failover Clustering, which includes support for both local and multisite failover configurations, is part of the SQL Server 2012 AlwaysOn implementation suite, designed to provide high availability and disaster recovery for SQL Server. The multisite failover clustering technology has been enhanced significantly in SQL Server 2012. The multisite failover cluster architecture, enhancements in SQL Server 2012 to the technology, and some best practices to help with deployment of the technology are the primary focus of this paper.

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  • Error during installation of an SQL server Failover Cluster Instance

    A common issue I've run into while helping with SQL Server Failover Cluster (FCI) installations is the failure of the Network Name. In the following post I'll discuss a bit of background, the common root cause, and how to resolve it. Countless happy developers. One award-winning bundle.The SQL Developer Bundle can transform the way you and your team work, aiding collaboration, efficiency, and consistency. Download your free trial now.

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  • Fast JSON serialization (and comparison with Pickle) for cluster computing in Python?

    - by user248237
    I have a set of data points, each described by a dictionary. The processing of each data point is independent and I submit each one as a separate job to a cluster. Each data point has a unique name, and my cluster submission wrapper simply calls a script that takes a data point's name and a file describing all the data points. That script then accesses the data point from the file and performs the computation. Since each job has to load the set of all points only to retrieve the point to be run, I wanted to optimize this step by serializing the file describing the set of points into an easily retrievable format. I tried using JSONpickle, using the following method, to serialize a dictionary describing all the data points to file: def json_serialize(obj, filename, use_jsonpickle=True): f = open(filename, 'w') if use_jsonpickle: import jsonpickle json_obj = jsonpickle.encode(obj) f.write(json_obj) else: simplejson.dump(obj, f, indent=1) f.close() The dictionary contains very simple objects (lists, strings, floats, etc.) and has a total of 54,000 keys. The json file is ~20 Megabytes in size. It takes ~20 seconds to load this file into memory, which seems very slow to me. I switched to using pickle with the same exact object, and found that it generates a file that's about 7.8 megabytes in size, and can be loaded in ~1-2 seconds. This is a significant improvement, but it still seems like loading of a small object (less than 100,000 entries) should be faster. Aside from that, pickle is not human readable, which was the big advantage of JSON for me. Is there a way to use JSON to get similar or better speed ups? If not, do you have other ideas on structuring this? (Is the right solution to simply "slice" the file describing each event into a separate file and pass that on to the script that runs a data point in a cluster job? It seems like that could lead to a proliferation of files). thanks.

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  • Bytes by MSDN - Let's talk Cloud

    - by Wallym
    While I was at DevConnections in Las Vegas, I was honored to be interviewed by Tim Huckaby for "Bytes by MSDN" on Cloud Computing. Here's a short intro from the talk:Do you believe in the Cloud? Wallace McClure, Founder and Architect of Scalable Development, Inc., does. His customers are extremely interested in the value and economies of scale that Cloud Computing, and more specifically, Windows Azure can bring. Building out an infrastructure that supports your web service or application can be expensive, complicated and time consuming. Or you could look to the Microsoft cloud. The Windows Azure platform is a flexible cloud–computing platform that lets you focus on solving business problems and addressing customer needs. Wally talks about all this, and more, in this interview with Tim Huckaby, and in his Windows Azure podcasts.

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  • Azure, a Beautiful Color, and So Much More...

    - by KKline
    Windows and SQL Azure Resources Cloud computing is more than just the latest buzz word in the IT trade papers. It is a remarkable paradigm shift with as much potential to "turn over the apple cart" of IT computing as client-server had for the world of mainframe and minicomputers. If you're not spending time to learn about cloud computing, in general, and SQL Azure, in particular, then you're missing the boat in a big way. (Ha! Two big metaphors in one afternoon. My high-school English teacher would...(read more)

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  • SQL Server 2008 Cluster Installation - First network name always fails

    - by boflynn
    I'm testing failover clustering in Windows Server 2008 to host a SQL Server 2008 installation using this installation guide. My base cluster is installed and working properly, as well as clustering the DTC service. However, when it comes time to install SQL Server, my first attempt at installation always fails with the same message and seems to "taint" the network name. For example, with my previous cluster attempt, I was installing SQL Server as VSQL. After approximately 15 attempts of installation and trying to resolve the errors, e.g. changing domain accounts for SQL, setting SPNs, etc., I typoed the network name as VQSL and the installation worked. Similarly on my current cluster, I tried installing with the SQL service named PROD-C1-DB and got the same errors as last time until I tried changing the name to anything else, e.g. PROD-C1-DB1, SQL, TEST, etc., at which point the install works. It will even install to VSQL now. While testing, my install routine was: Run setup.exe from patched media, selecting appropriate options After the install fails, I'd chose "Remove node from a SQL Server failover cluster" and remove the single, failed, node Attempt to diagnose problem, inspect event logs, etc. Delete the computer account that was created for the SQL Service from Active Directory Delete the MSSQL10.MSSQLSERVER folder from the shared data drive The error message I receive from the SQL Server installer is: The following error has occurred: The cluster resource 'SQL Server' could not be brought online. Error: The group or resource is not in the correct state to perform the requested operation. (Exception from HRESULT: 0x8007139F) Along with hundreds of the following errors in the Application event log: [sqsrvres] checkODBCConnectError: sqlstate = 28000; native error = 4818; message = [Microsoft][SQL Server Native Client 10.0][SQL Server]Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. System configuration notes: Windows Server 2008 Enterprise Edition x64 SQL Server 2008 Enterprise Edition x64 using slipstreamed SP1+CU1 media Dell PowerEdge servers Fibre attached storage

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  • Cluster Shared Volumes Mount Point

    - by Ryan H
    I am using Cluster Shared Volumes on Windows Server 2008 R2 with Hyper-V. The different volumes available have different sizes, and are physically located on different disks on the SAN. These volumes defaulted to labels such as C:\ClusterStorage\Volume1. I know that it is not possible / recommended to change where the CSV mount points are (C:\ClusterStorage), but I want to change the rest of the path to be a more useful name than "Volume1". In the Failover Cluster Manager, under Cluster Shared Volumes, I can see these CSVs, and they are working just fine. When I go into their properties, I can see a list, which has the mount point listed, but the entries are not modifiable. How can I change the mount point of a Cluster Shared Volume in Windows Server 2008 R2?

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  • Sticky sessions not sticky on coldfusion cluster

    - by GreatSeaSpider
    we're trying to deploy a legacy coldfusion site onto a new CF8 cluster. The cluster consists of three cf instances running under JRUN4 on a single windows 2008 server. I've got the cluster set to not replicate sessions, and sticky sessions turned on. each instance is set to use J2EE session variables. The application tag for the site has: sessionmanagement="Yes" setclientcookies="Yes" setdomaincookies="Yes" when each instance starts... no errors are reported in the instance log and they join the cluster without any issues. though the intances do have: 16/10 08:31:25 info SessionReplicationService successfully joined a JINI lookup service (assigned JINI-ID .....) and 16/10 08:31:25 info Clusterable service SessionReplicationService discovered a SessionReplicationService peer on a JRun server named "xxxx" on host xxxx which is interesting since session replication is definately off, is the SessionReplicationService responsible for sticky sessions aswell? thats enough background, the problem is that the sticky sessions appear to simply not work, each request is bounced to a different instance, and it seems as if the sessions are being lost on each instance anyways? As soon as the cluster is down to a single instance, the web app works exactly as expected and the sessions seem fine. has anybody got any ideas for me? i've been trawling the web and I cant seem to find any answers.

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  • Windows Cluster issue

    - by George2
    Hello everyone, For Windows Server 2008 failover cluster, I find it is dependent on Windows domain (in other words, Windows domain is pre-requisite of installing Windows Server 2008 fail over cluster). I am not sure why it is dependent on Windows domain? What features of Windows domain will Windows Server 2008 failover cluster utilize? thanks in advance, George

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