Many CentOS and RHEL Linux administrators have come to rely on the sar tool as an easy way to see historical load, io, and memory statistics. On Debian, sar functionality isn’t available by default but is easy to install.
apt-get install sysstat dpkg-reconfigure sysstat
(select yes to activate sysstat’s cronjob)
After several minutes, you’ll have access to:
- Check historical load averages: sar -q
- Check historical memory utilization: sar -r
- Check historical disk utilization: sar -u
As a side note, the sysstat package we installed also includes additional helpful utilities such as: iostat, mpstat, and pidstat.