I have a Fedora Server running Xen with 3 guests. Each guest has 2GiB of ram assigned to it.
Running at what i would consider idle i only have 742MiB of ram. Which makes no sense. Here are some interesting outputs.
total used free shared buffers cached
Mem: 1608 1482 126 0 8 608
-/+ buffers/cache: 865 742
Swap: 17823 435 17388
Cpu(s): 1.6%us, 6.6%sy, 0.0%ni, 91.5%id, 0.0%wa, 0.2%hi, 0.1%si, 0.0%st
Mem: 1647108k total, 1520236k used, 126872k free, 10088k buffers
Swap: 18251772k total, 441400k used, 17810372k free, 635544k cached
If I add up all the top applications I get roughly 16%. Where has all my memory gone?