When you're working with virtualization frameworks that have multiple physical host servers, you'll need some form of shared storage to fully realize the benefits of virtualization. For instance, if you want to be able to migrate virtual servers between physical hosts, the storage for those virtual servers must reside on a shared device that each host can access.

Some virtualization arrangements can address a variety of storage protocols, such as NFS, iSCSI, and Fibre-Channel. For lab or testing purposes, you can simply add several hard drives to a Windows or Linux system, share them with NFS or iSCSI, and bind your lab servers to that storage. If you want a more complete "homegrown" approach, give open-source storage options, such as , a try. This software offers a simple way to add a variety of storage to a lab or production network, using cheap hardware.

Armed with some form of shared storage and at least two physical host servers, you have the basis of a full virtualization platform ready to go. If you're evaluating several different packages, try each of them out for a week or so. Make sure to step through all of the features important to your needs, such as live virtual server migrations, snapshots, virtual server cloning and deployment, and high availability.