xfs: very slow after mount, very slow at umount

[Stan Hoeppner]

Mark Lord put forth on 1/26/2011 9:49 PM:

> agcount=7453

That's probably a bit high Mark, and very possibly the cause of your problems.
:)  Unless the disk array backing this filesystem has something like 400-800
striped disk drives.  You said it's a single 2TB drive right?

The default agcount for a single drive filesystem is 4 allocation groups.  For
mdraid (of any number of disks/configuration) it's 16 allocation groups.

Why/how did you end up with 7452 allocation groups?  That can definitely cause
some performance issues due to massively excessive head seeking, and possibly
all manner of weirdness.

-- 
Stan