I've had a test CentOS KVM host running for about a week now with 3 CentOS guests. There's 12GB physical RAM with about 7.5GB actually allocated to VMs. These VMs aren't even being used yet as the server's still in the testing stage but I've noticed that swap usage had been climbing over the last 24-48 hours. Now it looks like it's exhausted.
Here's the output of
# free -m total used free shared buffers cached Mem: 11905 11749 155 0 81 4632 -/+ buffers/cache: 7035 4869 Swap: 2047 2047 0
So as you can see the physical memory is all used but it's used as cached memory which I believe is generally fine, as that will be released if an application needs it.
I ran the shell script found in this answer which listed 3
The server was provisioned for me with only a 2GB logical volume allocated for swap and usually I like to match physical memory up to 8GB.
Is it worth expanding the swap logical volume or adding a separate swap volume?
Is this common with KVM? It's not something I've seen on other KVM hosts so is there a particular setting I need to adjust?
Any other comments/suggestions?