xfs: very slow after mount, very slow at umount

[Christoph Hellwig]

On Sat, Jan 29, 2011 at 06:35:54PM +1100, Dave Chinner wrote:
> Just because we can't do it right now doesn't mean it is not
> possible. Array/raid controller vendors need to implement the SCSI
> block limit VPD page, and if they do then stripe unit/stripe width
> may be exposed for the device in sysfs. However, I haven't seen any
> devices except for md and dm that actually export values that
> reflect sunit/swidth in the files:

I have access to a few big vendor arrays that export it, but I think
they are still running beta firmware versions.