Does XFS prevent disk spindown?

[Thor Kristoffersen <thorkr@gmail.com>]

I've noticed that when I spin down XFS-mounted disks they spin up again
shortly afterwards.  I used iostat to monitor disk accesses to a mounted
partition (with noatime) in single user mode.  Apparently there is a write
access to the partition approximately every 35 seconds, even if the
partition is idle.  As far as I can understand, since there is no data that
needs to be flushed this must be done by an XFS daemon for some purpose.

Is there any setting or mount option I can use to get rid of this behavior?
I know I can freeze the filesystem, but then I have to remember to unfreeze
it every time I need to write to it, so it's not an ideal solution.


Thor