Munin fills server memory

Question

In the last weeks, it happened several times to me that my vserver (Debian Lenny) was out of RAM (500M) and therefore wasn't able to run apache anymore. When looking at the processes with top, I saw that there were many open munin-limits and munin-cron processes that consumed most of the memory.

My guess would be that sometimes Apache temporarily needs more memory, which prevents munin-cron from running. And if munin-cron isn't able to stop itself, it would fill the memory until nothing is left.

I don't know whether this guess is true, but could maybe someone know what the problem is and how to prevent it? If necessary I'll remove munin, but I'd prefer to keep it running.

Answer 1

munin-cron calls munin-limits, if something prevents munin-limits from finishing you'll end up with munin-cron and munin-limits processes. As far as I can see (I don't use munin-limits), munin-limits is responsible for forwarding notifications regarding configured thresholds that's been exceeded. So, in order to try to figure out why munin-limits don't finish, you could try to run munin-limits as close as possible to how cron invokes it, with the addition of the --debug option.

Other general advise: check your logs and check if cron have sent any emails with output from munin-cron/munin-limits.