This is the default output of the munin load plugin. I’ve patched it to add a permanent blue line indicating the number of cpu of the server. The resulted graph looks like this : You can download the patched plugin here. It is tested with Linux and FreeBSD.
Monitoring
Memory usage by group of processes
While monitoring a http/php server, I needed to do some statistics about php-cgi memory usage. Playing with memory_limit in PHP, we wanted to know the average memory usage per php-cgi process. This is easily calculated with our best friend awk. First, get the number of php running processes: # ps aux | grep php-cgi | …
Munin and Use of uninitializer value in eval
On some of freshly installed servers (Debian Etch), I encountered these error messages in /var/log/munin/munin-node.log: Use of uninitialized value in eval {block} exit at /usr/sbin/munin-node line 456, <CHILD> line 8. What a great error message 🙂 After digging into Google results, I found it was just a problem with host_name variable in the configuration. Default …
Check if cron is working with monit
I encountered a problem last week with cron. crond was running but the jobs seems to not work. After debugging the crontab, I saw that on one job, the username was missing. Nothing was written in the logs to say that there was a problem. To avoid future problems, I wrote an alert for monit. …