Virtualizing Servers in a Small Office: Steve Longenecker's View

This post is by Steve Longenecker, who is a principal infrastructure consultant at Community IT Innovators in Washington, DC. Community IT Innovators, or CITI is an employee-owned, triple bottom-line company that provides computer tech support to nonprofits and socially responsible businesses. They're an important green IT practitioner in the U.S.

When one of CITI's clients needed to replace their two servers we set them up with a single server with virtualization software on it. The single server replaced an old domain controller that authenticated users and also hosted Microsoft Exchange for email and provided file and printer sharing. The other was their old terminal server that allowed users to access applications and documents on a shared network hard drive. These are very common functions for server computers.

Our clients primarily use Windows server for their server software. It is generally recommended that different server roles be delivered by different servers. That way, if one function fails, it won't crash the whole network. Sometimes the concern is security; sometimes it's resource management. It's a good recommendation to keep in mind and saves a lot of grief when, for instance, you are doing a Microsoft Exchange migration and want to avoid breaking your Blackberry enterprise server. If they are running on separate systems you can save yourself considerable headaches.

Unfortunately, our clients haven't always been able to afford hardware for every server role they've wanted. So we combine roles by virtualizing their server or servers. At CITI we've come up with all sorts of creative combinations (some sanctioned by Microsoft and others not) to help our clients maximize the productivity of their limited hardware resources.

Virtualization has completely changed the way we budget hardware and server roles. Virtualization is software technology that makes it possible for a single physical computer to host more than one, distinct and independent operating system working at the same time. By allowing the creation of multiple operating system instances on a single piece of hardware in a way that is relatively easy and economical, there can be a major cost savings. With virtualization software, the work of three or four servers can be done on one or two servers.

We recommended that our clients purchase a single robust server on which to create three instances of Windows Server 2008. The first would be a domain controller, file server, and print server. The second one would be an Exchange 2007 server for email, and the third would be a terminal server. We briefly considered several other ways of configuring this new virtualized server, but ended up going with the three instances as the best solution for a small office to minimize costs and control "server sprawl."

The result from our client's perspective was a cost savings of at least $4000 in upfront hardware expenses. The client will also realize significant savings associated with the reduced electricity use of powering (and cooling) one server instead of three. They also appreciate the environmental benefits of that savings.

Smart choices about how best to segment server roles among server instances are still required, but virtualization allows us to make those choices well, even when the hardware budget is limited.