Performance tuning

This page describes how to improve performance of OpenVZ system.

HW node environment tuning

Disable unnecessary services

Disable all default services that you do not need to use and then reboot your host.

For example, the audit daemon can significantly decrease performance of linux kernel system calls (up to ~20%) even if you do not use any audit rules, or even if you just stopped this service without host reboot!

To setup default services, use chkconfig or ntsysv in RedHat, or rc-update in Gentoo, update-rc.dv on Debian

network checksumming

(TODO)

Virtual Environment tuning

CPU distribution inside VE on SMP hosts

• If the total number of VE's in your host is more than CPUs number, and there are many threads running inside each VE it is better to give just a single VCPU to each VE.

In this case thread memory locality will significantly reduce overhead on SMP memory coherence and overall performance can be increased up to ~50-100%!

To set the number of CPUs available inside VE use:

# vzctl set $VEID --cpus N