[CRITICAL] The IO freeze is back

Today we have experienced the same IO freeze issue with climbing load that was reported many times last year in these threads:
http://forum.proxmox.com/threads/143...during-backups
http://forum.proxmox.com/archive/index.php/t-14284.html

The difference is that today it appeared not during nightly backups, but during low traffic daytime. The only difference to the day before is that we migrated one OpenVZ VE with tens of thousands of small files to another node where there already is a heavy MySQL server (also OpenVZ).

The system specs:
- Q77 motherboard, Intel Core i7 CPU, 16GB RAM
- Adaptec 6805E controller, all PVE partitions on RAID10
- ext4 filesystem

We were running 2.6.32-27-pve kernel at that time.

htop during freeze:
proxmox-IOfreeze-2014apr-htop.png

console during freeze:
proxmox-IOfreeze-2014apr-console.png

Attached Images

• proxmox-IOfreeze-2014apr-htop.png (29.3 KB)
• proxmox-IOfreeze-2014apr-console.png (20.2 KB)