sar is a tool to collect, report and store system activity information, a very useful tool to debug server performance related problems.

To install sar on CentOS/RHEL, run

yum install sysstat

To view memory stats, run

sar -r

To view IO stats (disk usage), run

sar -d

For CPU stats, run

sar -P ALL

Load average

sar -q

IO Activity

sar -b

Posted in Linux