There is no doubt on the tremendous benefits virtualization can bring about. In fact, I covered the idea of leveraging virtualization to implement disaster recovery just last month. Assuming you are finally convinced of the merits of virtualization, you might be wondering if there are specific areas that you need to look into. To help you along, I'll highlight one strategy that should work for SMBs looking to implement virtualization.
Based on my experiences, I will advocate that all functionalities of each core IT service be encapsulated within disparate and single virtual machines. This could be an intranet portal, where the Web server and supporting database server are bundled into the same virtual machine. Another example would be putting the various pieces of the accounting server software into its stand-alone virtual machine. Ditto for your e-mail server and, if you have the RAM and storage to spare, even the backend portion of your antivirus software.
The benefits of such an approach are many. Firstly, segregating the various IT services into different virtual machines eases the burden in terms of administration. Since each virtual machine package is independent, tasks such as backup and maintenance become much simplified. In addition, the elimination of dependencies across virtual machines makes configuration so much easier and enforces proper housekeeping.
Now, there might be instances where limiting the number of virtual machines to one per IT service might stymie your ability to scale your infrastructure, resulting in a performance bottleneck. If that happens, then there is no choice but to work with multiple virtual machines. This should be rare though, since the hardware tasked to running virtual machines tend to be overpowered boxes in the first place. In fact, an IT service that can't even run within a single server for your SMB should be re-evaluated for its suitability for virtualization in the first place.