Matt Connolly's Blog

my brain dumps here…

ZFS saved my Time Machine backup

For a while now, I’ve been using Time Machine to backup to an AFP share hosted by netatalk on an OpenIndiana low powered home server.

Last night, Time Machine stopped, with an error message: “Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you“.

Periodically I create ZFS snapshots of the volume containing my Time Machine backup. I haven’t enabled any automatic snapshots yet (like OpenIndiana/Solaris’s Time Slider service), so I just do it manually every now and then.

So, I shutdown netatalk, rolled back the snapshot, checked the netatalk database, restarted netatalk, and was then back in business.

# /etc/init.d/netatalk stop
# zfs rollback rpool/MacBackup/TimeMachine@20100130
# /usr/local/bin/dbd -r /MacBackup/TimeMachine
# /etc/init.d/netatalk start

Lost only a day or two’s incremental backups, which was much more palatable than having to do another complete backup of >250GB.

ZFS is certainly proving to be useful, even in a low powered home backup scenario.

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2 responses to “ZFS saved my Time Machine backup

  1. Dave 2 February, 2011 at 16:36

    Hmm, food for thought – thanks!

  2. Faiyaz Ahmed 25 October, 2013 at 02:18

    I know this is an old thread, but I have the same setup (OI + netatalkd + ZFS) and have noticed that the error thrown may be misleading. It’s possible the backupd service on your client wants to garbage collect the afp volume because it’s getting near capacity. To do that efficiently, it’ll truncate the volume to size 0, then start a full backup. Rolling back the volume via zfs simply delays this behavior. Did you see the error again? Did you have to eventually do a full backup?

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