ZEVO support for Time Machine

Can I use a ZEVO-managed USB hard disk for Time Machine backups?

ZFS dedup

Will ZEVO and Time Machine give me de-duplication (which is sorely missing from Time Machine on HFS+, especially if you backup multiple machines to the same disk)?


2 Answers 2


In the Time Machine pane of System Preferences, add any ZFS dataset.

For the first backup to that dataset, the operating system will:

  1. create a sparse bundle disk image (….sparsebundle) at the root of that dataset
  2. attach the image, after which you'll see a volume named Time Machine Backups.

For each subsequent backup to that dataset, the OS will:

  1. attach the image, after which you'll see the Time Machine Backups volume.

Time Machine routines with ZFS are similar or identical to the routines that apply when backing up to a device – such as an Apple Time Capsule – that uses AFP.

How can one recover from TM after new/reinstallation? New OS installation knows nothing about ZFS to TM image is unreachable.

  • Good point. Probably only works in combination with a file server (as a restore over the network), or by copying the sparse bundles over to a disk in a supported format.
    – Thilo
    Feb 12, 2012 at 11:27
  • Please: the question about restoration should be separate. There will be a multiple answers, which could become confusing under the opening questions about backup. Jul 3, 2012 at 2:57
  • I refuse to think about restoration separate from backup. What is the point of a backup if not to later restore it?
    – Thilo
    Jul 3, 2012 at 7:18
  • No offence intended. I may revisit this question after the banner of changes, which appeared around the time of WWDC, is lifted from the ZEVO web site. Jul 3, 2012 at 20:05

Time Machine backups can only be stored on HFS+ volumes. The reason is that Time Machine relies on the ability to create new hard links to existing directories, which you cannot do in ZFS.

  • 1
    How about HFS+ in a sparse bundle on ZFS? This is how Time Machine works over the network, right? Would that work (and give me the benefits of de-duplication and encryption)?
    – Thilo
    Feb 8, 2012 at 23:55
  • @Thilo: Yes, in principle, that should work. As far as de-duplication and encryption go, I don't remember from what ZFS versions those are available. But if Zevo offers them, you should be OK. Feb 9, 2012 at 12:48
  • Wish for the restore interface of Time Machine to work with ZFS snapshots … a fuller answer will fit better under a question about restoration. Jul 3, 2012 at 3:22

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