I'm using FreeBSD. I would like to write a munin plugin to log it, but i don't understand how to get this data.
1 Answer
I don't believe there's a way to measure this directly without abusing dtrace.
Some things that may be helpful:
gstat(8)
- Geom device statistics, can show you raw disk activity / workload
Doesn't directly measure latency though.ioping - Lets you measure latency from userland (you could run it & log/chart the results)
Downside: Adds load to do the test, passes through the VFS layer, and can't test the underlying drive unless you reserve a partition for it to use.
dtrace
, however I'm not familiar enough with the technology to write a full answer on this subject...