After upgrading kernel from debian 2.6.32-openvz-amd64 to RHEL6 2.6.32-042stab035.1, I have problem with kernel page cache.
Looks like no OpenVZ containers use page cache and now I have 10-15GB free RAM and only 3-5GB cache generated by mysql server that runs on VE0.
There's no such problem with debian kernel, but all RHEL6 kernels I've tried had the same sympthoms.
MemTotal: 24677212 kB MemFree: 10462364 kB Buffers: 467596 kB Cached: 6487520 kB SwapCached: 0 kB Active: 9149776 kB Inactive: 3396248 kB
Any ideas what's going on with RHEL6 kernel? How could I make container use cache?