NetApp Performance Monitoring: Disk Performance / How to find out which disks are busy

Disclaimer: I take no responsibility if you screw up, or otherwise render your system unusable.  That being said, if you aren't a moron, this works every time.

When running sysstat -x, you can see how busy the busiest disk is.  However, it doesn't tell you anything else.  The curious sysadmin would wonder:

Which disk is the busiest?
Is there more than one disk that's just as busy?  If so, which ones?

This is where the handy tool "statit" comes in.  But first you need to be in "advanced" mode:

NETAPP-CLI> priv set advanced
Warning: These advanced commands are potentially dangerous; use
         them only when directed to do so by NetApp

Let's start the statistics collection

NETAPP-CLI*> statit -b

Now, wait a few moments.  Depending on how long you want to collect data - wait that long.

NETAPP-CLI*> statit -e

You will see a lot of data output.  Scroll up, and look through your raid group(s).

You will want to focus on the 2nd column "ut%".  If you are running raid_dp (you should be), all of your disks (except for the two parity disks) should be within a few % of each other.

If some disks are substantially busier than others within the same raid group, you may have hot spots - and you should consider running a reallocation scan and subsequently reallocating if your reallocation score is poor.  Click here to learn more about reallocation.

Don't forget to exit out of advanced mode

NETAPP-CLI*> priv set
NETAPP-CLI>