I have a VPS with VPSnoc and it is exhibiting some strange behaviour. When I total the %MEM column from a "ps faux" I get around 23%, but when I run free I get 419580/524288 = 80% used. That's a lot of RAM to be being used by non-processes, way more than on any other box I administer, or even my friend's VPS with the same provider.
I've emailed the VPSnoc support a couple of times now, but they don't even seem to be able to understand that this is a very weird thing to have happening on a system.
I wouldn't complain, except that I occasionally get out of memory errors (like when I try to set apache2 workers to >7 threads or >8 simultaneous connections) and those are just not nice.
Is there any way this could be a configuration problem that I could fix/work around, or any way this could be normal? I'm losing hope that VPSnoc will even acknowledge the problem.
They use OpenVZ, if that helps.
Edit: I have tweaked some MySQL settings, and that made what ps reported for it's RAM usage go from 7% to 4%, but the amount of RAM use reported by free dropped about 20%. I'm not longer getting out-of-memory errors, but would still like to understand the reporting better. The current output of free -m is:
total used free shared buffers cached Mem: 512 320 191 0 0 0 -/+ buffers/cache: 320 191 Swap: 0 0 0
I understand better now the buffers/cache differences that can exist, but none are being shown by this output (or ever were being shown on this box) and that shouldn't cause actual out-of-memory errors.