Configuring Failover Cluster in Windows Server 2008

by Dmitry Kirsanov 19. April 2012 06:45

About 5 months ago, I made a video about configuring the network load balancing cluster in Windows Server 2008. I am continuing the series about clustering the Windows Server 2008 with the next type of clusters – the failover cluster. Also known as “high availability” cluster.

Although Windows Server 2008 supports 4 types of clusters – Network Load Balancing, Failover, Computational and Grid, the most commonly used are the first two. Also, we’ll talk about the private clouds later, as they are doing similar job, but in Windows Server 2008 the private cloud is the functionality of an application called System Center Virtual Machine Manager 2012, so it’s not the system core feature, such as clustering.

During the series of demos we’ll talk mainly about failover and network load balancing clusters, as the High Performance Computational cluster requires it’s own special edition of Windows Server 2008, called Windows Server 2008 R2 HPC Edition, and chances are – you won’t ever have the requirement to set up such environment.

Windows Server 2008 Cluster Categories

Windows Server 2008 Cluster Categories

As you can see in the following slide, there are two categories of clusters by the way they share resources.

Failover cluster belongs to the second group, which means that it is a group of computers, where only one node (i.e. the machine participating in the cluster) owns the resource. You may have two or more machines working as nodes in your failover cluster, but only one of them will serve clients at any moment of time. Once that machine fails, another node takes ownership of resources (shared drive, for example) and starts serving clients instead of the failed node.

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Network Load Balancing Clusters in Windows 2008 - when one server is not enough

by Dmitry Kirsanov 14. November 2011 08:52

Russians says – “One is not a warrior at the battlefield”, meaning that one is just too small number for a real war. When the time of real battle is coming to your web site, it’s time to become a … farmer. The geeky one.

Web farm, or Network Load Balancing (NLB) cluster is when there are more than one web server behind a single web address. Of course, it’s not only about web – some other stateless resources can be scaled that way as well – DNS server, for example, or SMTP. However, the most popular use of NLB clusters is web, as most requests in the Internet are going through it.

Network load balancing clusters are rather frustrating topic for many systems administrators, as it’s very common for them to know clustering till the time of their exam. MCSEs and MCITPs of all kinds have to know that stuff, but rarely use it. Who might be more interested in clustering – that’s web developers, who’s web applications serve more and more visitors each day and should be infinitely scalable by design.

Developers

But what it takes to build an application, which could be scaled out by simply adding more hardware? If your application is working fine and attracts more customers than it can handle – that’s when you are wondering whether you’re in trouble. The trouble comes when you realize, that the architecture of your project does not support scaling and situation is even worse if your web developer has no clue about how to make it work in the cluster.

For .NET developers, though, the situation is much better than for PHP developers, for example. They can use SQL server to store the state data (and SQL server may reside on failover cluster, which is the second type of windows cluster that we’ll review later), files can be stored at mirrored network area storage (NAS) and that’s it.

Systems Administrators

For administrators, though, the situation is more difficult. First of all, they are the ones who needs to care about installation, maintenance and management of the cluster. They are the ones who migrate old applications to new clustered servers and must ensure they understand why these applications do not work under new conditions. While usually developers have the harder burden, this time it’s not the case, thanks to Visual Studio and .NET.

There is not much we can say about developer’s part of the job, as there is too little and too simple stuff to do, there is pretty much to say and to show to system administrators.

That’s why I had no choice than to prepare my first narrated lab about creating Windows Server 2008 Network Load Balancing cluster. Enjoy!

Implementing Network Load Balancing Clusters in Windows 2008

Perhaps my future labs will become narrated as well, excerpt for the short and simple ones. It takes a bit more work, since I am not preparing the text and have limited time to complete the lab (always do it in one take), but is definitely more fun, as I can tell more than you want / need to know about the subject.

File Synchronization Utility

by Dmitry Kirsanov 26. September 2011 18:31

Yet another command line utility written to do some useful stuff in the background. This time it is about file synchronization.

It’s quite often that we need to make 2 directories in our local network in sync. For example, you may want to synchronize folders with photos, backup files or even production files of your web application between IIS web farm nodes.

This program utilizes the Microsoft Synchronization Framework, so basically it does very little apart from what Microsoft already provides. Personally, I am using it to pull backups from TFS server on daily basis and to synchronize shared folders among load balancing cluster of production web server. In  both cases utility is running as Task Scheduler task and everything happens in background.

It doesn’t require installation, just unpack it to your utilities folder and it’s ready to go. It requires .NET framework 4 Client Profile in order to run. Another dependency is Microsoft Sync Framework 2.1 (Two components required - Synchronization and Provider Services).

FileSync.rar (114.45 kb)


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