David Seah has a good walk through for optimizing your dv server for wordpress

I’m running a (dv) Base system from Media Temple, which is their 256MB version. This is their lowest-end server configuration, which is actually a virtual server sharing the same hardware.

As my blog has grown in popularity, when I switched over I got enough traffic to overwhelm the server. It turned out that the base configuration isn’t tuned to work within the guaranteed 256MB of memory allocated. It’s configured to run on a considerably larger server, and grabs extra memory as needed if it’s available from the global memory pool. This is all fine and dandy when memory is available, but if it ISN’T, the server will start to chug.

After making the following tweaks to my server setup, one of my articles was dugg and the server was hit by 2750 pageloads per hour for a few hours. This is a pretty significant amount of traffic, and the server had no problems staying up. In fact, it barely broke a sweat. Keep in mind though that in addition to the server tweaks below, I also had optimized my wordpress installation with WP-Cache, which reduces server load significantly. You can read more about this in WordPress and Shared Hosting.

check it out :
http://davidseah.com/notebook/configuring-media-temple-dedicated-virtual-server-for-wordpress/