You can find out if your VPS is overselling the memory with utilities such as this one: http://k0nsl.org/bag/vzfree.c (author lowendbox) Shell script: http://k0nsl.org/bag/vSwap.sh Or this Ruby one: http://k0nsl.org/bag/vSwap.ruby They more or less work the same, all of them. The C code is probably best with regard to memory utilization though. For more comphrensiv reading with details, see: