Sunday, December 9, 2007

iTunes, ZFS and Time Machine

I have been blogging about ZFS on OS X recently
RW ZFS and Leopard first thoughts
How to get experimental rw ZFS support AFTER upgrading to 10.5.1

As a way to start using ZFS on OS X on a daily basis I have migrated the contents of
my Music folder to a ZFS mirrored pool composed of an external disk and a matching
internal partition.

After a slightly rocky start including reinstalling my laptop so I could do the repartitioning
I wanted and a fairly high number of initial crashes things currently seems to be going well.

One of the things that I have noticed is that my iTunes Music folder and Library are polluted.
Now embedded in my library with the same name as a number of songs I have '.htm' files.
(./path/to/foo.mp3 also has a matching ./path/to/foo.htm in a large number of cases)
The files are part of some O'Reilly books I have on CD, as such I know "where" they came from, sort of.
(My library from my pre-experimentation CCC backup also has the same corruption)

A restore from my Time Machine backup is in order to get things back to a known good state. Or a recovery
from my slightly older CCC backup which is also not corrupted.

I am not particularly impressed with the Time Machine interface. It is novel and seems relatively functional
for finding the most recent backup by using the timeline on the right.

[Time Passes]

The Time Machine restore failed after ~8GB on a couldn't read/write a file error aborting the whole restore.
I do have to admit that the backups are working I can browse the backup structure. The use of hard links and
metadata is cool. Restoring via rsync does the trick, possibly faster as well since it doesn't copy unchanged files.

Even better I don't see a log, I am feeling somewhat less than impressed with the feedback from and utility
of Time Machine from a administrator's point of view. Am I asking for too much? A log of the restore with an
indication of the failure?

I have a feeling that the restore is really just a copy in Finder. An automator type action passing the
selection to Finder and executing a copy.

Again what finally worked for me was a combination of methods. I used the Time Machine interface to find the
backup I wanted and CMD-I to see the path to the directory (although would have been just as good).
Once I found the backup I wanted rsync worked quite well restoring 48GB of Music in 12,273 files.
(rsync --archive -P /Volumes/TimeMachine/.../Music/iTunes ~sferry/Music/iTunes)

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