High load

This is an article in the Performance tuning series.

You usually get asked to figure out why load is high on a system that lacks any sort of systematic baseline graphs and statistics like you would have with a professionally managed environment. If you're looking to install performance monitoring systems proactively, we'll cover that separately in articles like wp:Munin (software). In Linux Journal, Kyle Rankin introduces some methods for diagnosing High Load problems on your linux server. He goes through typical usage of commands like top and iotop.

General

Some of the commands you will find useful for high load issues

# look at any hardware or unusual issues first
dmesg
# look at the partitions you have
mount
# see total stats for the machine
uptime
# look at processes sorted by virtual size
ps awwlx --sort=vsz
# get three cycles of info from iostat
iostat -d -x 5 3
# show one iteration of iotop
iotop -bto --iter=1

Applications

Troubleshooting High Load issues by configuring specific services or applications

See

• PHP Accelerator
• CiviCRM/debugging