Munin, how to reduce IO with rrdcached

Few weeks ago Munin was flooding me with message alerts about IO latency, read or write, going too high. Ironically it turned out Munin was the culprit. And the solution was to use rrdcached.

Lets see a Munin graph that shows pretty well the difference using rrdcached made:

sda-month

Around week 21, when I deployed this optimization, writes dropped quite a lot and reads stabilized.

Now follows the step-by-step guide to use rrdcached (with Gentoo).

Continue reading “Munin, how to reduce IO with rrdcached”

Gentoo: How to use Munin to monitor Mailman

Update 31/12/2012: Now this is a bit simpler, since bug 448414 has been fixed.

Before we start with the step-by-step procedure to get the mailman plug-in working, lets recall how to test a munin plug-in:

$ sudo munin-run mailman
posts.value 24
members.value 21892

The output above is what you should get once the mailman plug-in is correctly set-up. Continue reading “Gentoo: How to use Munin to monitor Mailman”