After experiencing power issues at my home, I had an electrician check to see how much of a load my Exchange servers were pulling. Although the circuits in my server room weren't overloaded, I would need another dedicated circuit if I added a couple more Exchange servers. At that point, I considered server virtualization on my production servers to reduce the line load.
However, it wasn't until I was unable to save a document because the system board in the server had failed that I decided to go forward with virtualizing my servers. Because this particular machine serves as both a file server and an Exchange server, I knew I had to act quickly. Keep in mind, I don't recommend using your Exchange server as a file server, unless you're in a very small office.
Since I suffered a catastrophic hardware failure, I was in a hurry to get back online. As such, I didn't have time to do the proper planning or to research virtualization best practices for Exchange Server 2007. While this article details the steps I took to accomplish Exchange Server 2007 virtualization, there is one caveat. These techniques worked well for me; they may or may not adhere to Microsoft's best practices for virtualizing Exchange Server 2007.
Technically, Microsoft won't officially support Exchange Server 2007 virtualization until after the release of Hyper-V later this year. Additionally, I don't believe there are any best practices available at this time.
The virtualization process
I purchased a computer that was as similar to the one that had crashed, but it had more processing power and memory. While this detail might seem trivial with regard to virtualization, it did make my life easier. Even though I constantly back up my files and Exchange Server information store, I didn't have a full system-state backup of the server that had died. I knew that, if needed, I could perform a fresh Windows installation, install Exchange Server and use a recovery storage group to import my data.
Next, I transplanted my RAID controller and drives from the old server into the new server. Normally, you can't do this unless the hardware is identical. Transplanting all of your drives from another machine generally will result in receiving a blue screen halfway through the boot process. Fortunately, this didn't happen since the hardware was similar enough to boot Windows.
When Windows booted, I received a message stating that substantial hardware changes had occurred and Windows needed to be reactivated within three days. Because I was planning to virtualize the machine, I chose to ignore this activation prompt.
I then verified that Windows Server 2003 Service Pack 2 (SP2) was installed on the server. This step is critical because you won't be able to connect the server to the network unless SP2 is installed after moving the machine to a virtual environment.
Since I was going to store my backup on a network drive, I needed to be able to reach the network. Hyper-V doesn't allow virtual machines to connect to USB devices, so storing a backup on the network may be your best bet.
Next, I created a full system-state backup of the server. I wasn't quite sure how well the backup would restore to a virtual machine, so I tried to remove as many potential obstacles as I could. Therefore, before I started the backup, I dismounted the Exchange Server database and shut down all Exchange-related services.
When the backup started running, it occurred to me that I was potentially putting a healthy machine at risk. Given the mission-critical nature of an Exchange server, I decided to protect myself in case the virtualization process didn't go well. While the server was being backed up, I bought several hard drives for the new machine. I figured that once the backup completed, I could remove all currently used hard drives and put them on a shelf. That way, if the virtualization didn't work, I would only have to remove the drives from the server, plug the old drives back in and have the system running again in a few minutes.
Note: If you do this, be sure to label the drives. Attaching the drives to the RAID controller in the wrong sequence can corrupt data.
Once the backup completed, I shut down the server, removed the old hard drives and installed the new drives. I then installed a 64-bit copy of Windows Server 2008 and Hyper-V RC1. Hyper-V isn't like Microsoft's previous virtualization products in that it performs virtualization at the hardware level. Therefore, it's critical to verify that your hardware will support Hyper-V before attempting to virtualize your system.
Once the Windows environment was in place, I began creating a virtual machine to act as a replacement for the failed server. There are only a couple of mailboxes on my server, so I allocated just 2 GB of RAM. Keep in mind that Microsoft's Hyper-V allows you to make adjustments later, if necessary.
I also created virtual hard drives to mimic the old server's physical drives. To maintain fault tolerance, the virtual drive containing the Exchange information store must reside on a different physical drive or physical array than the virtual drive that holds the transaction logs.
Microsoft's Hyper-V lets you choose whether you want to create virtual fixed-size hard drives or dynamically expanding virtual hard drives. I chose to use fixed-size virtual hard drives because they tend to perform better than dynamic virtual hard drives. It does, however, take some time to create fixed-size virtual hard drives. Each system is different, but this process took about 20 to 30 minutes for a 200-GB virtual hard drive.
About the author: Brien M. Posey, MCSE, is a five-time recipient of Microsoft's Most Valuable Professional award for his work with Exchange Server, Windows Server, Internet Information Server (IIS), and File Systems and Storage. Brien has served as CIO for a nationwide chain of hospitals and was once responsible for the Department of Information Management at Fort Knox. As a freelance technical writer, Brien has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal website at www.brienposey.com.
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