VPSIOLimit

Usable when some VPS consumes an enourmous amount of IO (IOPS, bandwidth).

Openvz:
1) Jump to a VPS CGroup hierarchy:

cd /proc/vz/beancounter/<veid>

2) Get the affected device major:minor numbers:

dmsetup ls | grep <lvs>

3) Edit the CGroup by specifying the device and IOPS count:

echo "<major>:<minor> <iops-count>" > blkio.throttle.write_iops_device