It appears that the iostat plugin focuses on physical volumes. It
ignores md* raid devices and dm-* logical volumes (from LVM) although
the iostat command does list them. Of course, the munin plugin takes its
output directly from the /proc sources instead of through the iostat
Wouldn't it make sense for the iostat plugin not to ignore those
devices ? Or even better, to make it capable of accepting user input of
the type of device (disk, md, lvm) ?
For now, I am just trying to understand where in the plugin's code the
device type selection is made. It looks like it is a regex applied to
/proc/diskstats but that's about as far as my current understanding
Before I try harder, has anyone else done it before ?
Can anyone point me to the lines on which I should focus my effort ?