Performance problems

Hi,

We are running YouTrack 2.2 Christmas Edition (as a war file) on an Ubuntu 10.10 Server in a virtual environment.

The virtual server has 1 CPU (with no limits set agains the physical CPU which is a 4 core Xeon CPU), 1GB of reserved memory and lots of disk (about 50GB)

From time to time we get really bad performance (which usually starts with "connection lost" messages, and after a while we will get the "unexpected error" window.)

Any suggestions on configurations I can look at? (Java, Tomcat ect)

Regards
//Mattias