Using Server Virtualization on “secondary” Servers to Increase reliability and Save Money


Server virtualization can help you consolidate and increase the utilization of servers. You can lower costs using the virtualization technology built into SLES software. Mike Brady explains how he uses virtualization for services that he used to relegate to old, slow, out-of-warranty machines.

Like a lot of other organizations, we have had a tendency to set up lots of what I call “secondary” servers. These are servers that we wouldn’t want to be without, but a small amount of downtime won’t hurt us too much. We’ve used servers that used to serve as one of our primary servers, but have now been retired. They are normally out of warranty, and a bit slow by current standards. Of course, even though we look at these as “secondary” servers, the users don’t really differentiate between different levels like this – everything is important to them.

Some of our “secondary” servers include:

  • Blackberry Enterprise Server (BES) – we have about 20 Blackberry users. BES on Windows 2000 runs great as a XEN virtual machine.
  • Legacy servers that are being kept on-line for reference purposes – like an old accounting system.
  • iFolder – iFolder tends to be a “replace the server” kind of upgrade – not exactly an in-place upgrade. By virtualizing it, we can run the old and the new server simultaneously when we upgrade to new version, and not take up space in the server rack.
  • Web / Intranet – SLES or OpenSUSE virtualized is a perfect fit as a XEN virtual machine. Great performance, and a super easy install.
  • Remote access Windows XP machine – we have the occasional remote user that needs to run a legacy app that doesn’t work well over a VPN connection. We simply setup some XP virtual machines for these folks. They connect to the VPN and use Remote Desktop to access the XP virtual machine.
  • Internal DNS

So, rather than continuing to use old, ready for retirement equipment for all of these services, we have turned to XEN virtualization on SLES. I am able to buy a couple of affordable but good machines, and virtualize all of these servers. I now have hardware that will be more reliable, and is under warranty. I can easily move these virtual servers from one hardware host to another.

Another big advantage is the ability to more quickly backup and restore these servers. When we were running on a mix of old hardware, restoring a dead server to a different piece of hardware was a challenge. Different network cards, different processors, video, etc… This presented a driver problem, and even when the machine was a Linux box it wasn’t exactly a quick process to get things going again. Having these servers virtualized makes recovering from a hardware failure much easier. Since these are secondary services, I can shut down and backup the entire virtual machine in the middle of the night. Then, when a hardware failure happens, I don’t need to have identical hardware to restore the server to. As long as I have a similar processor on the host hardware, I can easily bring the virtual machine back on-line.

Also, since we ran all of these services on old hardware, they tended to be a little slow. Now, running modern hardware, all of them run much faster, even though they are virtualized. The more current hardware also runs cooler and consumes less energy. So there is a “green” effect to all of this as well.

One last nice thing about running these secondary services as XEN virtual machines: you are gaining experience toward running all of your servers as virtual machines. A lot of people I have talked to are a little scared by the proposition of moving all of their servers to a virtual setup. A great way to dip your toes in the water of virtualization is to start moving these less critical services to virtual machines.

For more information about server virtualization using SUSE Linux Enterprise Server, visit this page.

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