We've got a server with 33GB RAM we're wanting to use as a KVM VM Server under CentOS 5.5. We installed 3 linux guests, each using 2GB RAM (so 6GB total). But, when we launch them all, the VM server reports only 2GB total RAM in use, and the disks are 100% busy all the time. On another KVM server we have, we see that each VM reserves it's memory in RAM when it boots, but that does not seem to be happening here. It seems to be trying to page the VM's memory to disk all the time, which is odd since I have so much spare RAM. I can't figure out how to tweak that, or figure out why it is doing it. Any clues? The server load goes up to 60 when all 3 VMs are running because the disks are pegged.
Tterestingly, the host server does not show any swapping going on, but when I shut down the VMs (which happens incredibly slowly), the disk activity stops...?