In the Solaris Volume Manager Administration Guide (in the
Solaris 10 System Administrator Collection),
"You can use the ufsdump command to backup the files of a mounted
filesystem residing on a RAID-1 volume. Set the read policy on the volume
to "first" when the backup utility is ufsdump. This improves the rate at
which the backup is performed."
"After the ufsdump command is done, set the read policy on the mirror to
This may have been the same for previous versions of Solaris and I just
never noticed, but my question is why would this improve the rate? Why is
it faster/better to limit reads to the first disk?