Today I noticed that many VMs do get a lot more RAM than they actually
use. While using only about 200-300MB small vms like -net and -firewall
get gigabytes of memory and this seem to be the case even if memory is
running out (sum of all VMs approaches physical RAM size). Also dom0 is
using only about 700MB but gets 4GB.
1) does memory balancing take back memory from a VM at all?
2) how does it happen that VMS get assigned this ridiculously larger
amount of memory compare to their usage?
3) is there something that can be done besides manually setting limits
for all VMs?
I current think about limiting all small VMs to 256MB and dom0 to 2 GB
of RAM (by GRUB parameter) lacking any idea for a better approch.