Home > Storage and Backup, zfs > No More USB Hard Disks

No More USB Hard Disks

Since I got some Macs at home I’ve been wanting to use Time Machine systematically for backups. Previously I have had a FreeBSD server at home to store bulk and shared data and backups. Initially, I had anticipated getting more drives for the server, formatting them as ZFS, and using that with Time Machine. Then, when Mac OSX 10.5 Leopard released, it turned out that Time Machine only supports external USB or firewire disks. That meant my server idea wouldn’t work.

I borrowed a USB drive from work to test out with time machine, and it worked for a while, to the point that I even used it to restore a large chunk of my system because I had screwed it up by messing around with it. Then, something funny happened and the USB disk wouldn’t mount anymore. I did a bunch of troubleshooting and discovered that the journal had gotten buggered up on the HFS+ volume on the USB disk. I found a little utility that I ran to disable journaling, which then allowed me to use disk utility to repair the volume.

Recently I was using the USB disk to shuffle some data around, and at the one point that the only copy of some digital video files from the video camera I have were on the disk, it died again. I’ve been trying to repair the volume for four days with various tools. Nothing is working so far. It appears that there is an actual hardware failure somewhere in the device. It’s a Maxtor One Touch III with two hard drives configured in a RAID0, so I can’t recover the data from the disks one at a time by direct-connecting them to another machine.

I was considering going out and buying a big external USB disk for backups until this event occurred. On the other side of my desk, there’s a FreeBSD box with a nice set of mirrored ZFS drives where the data really should be. I’m taking this as a slap upside the head, and I’m not risking any of my data on external USB disks anymore. I’m going to get a couple more disks for the server, RAIDZ them, and use that instead.

I won’t be able to use Time Machine, but what the hell, I can setup a different backup software for Jenn’s and my machines.

Categories: Storage and Backup, zfs
  1. 2008-03-05 at 21:11

    RAID 0, just say no (unless you can afford to lose the data :)

    Scott, have you tried any third-party disk recovery tools on your failed drives? Often Disk Warrior (which I have) or Techtools Pro (have not used it, but have heard it is also good) will work wonders as the first recovery option. For really messed up drives, it can take a long time to crank through all the data corruption, but it does work. I had one drive take nearly 5 days, but it fixed it in the end. After that Disk Utility can usually bat clean up.

    For more extreme measures, crack the case, yank the drives and attach them to a PC/x86 box running SpinRite.

    As for making use of ZFS, from what I’ve read, trying to make Time Machine run over NFS/SMB still seems to be non-starter unfortunately. Some people seem to have had better luck using Apple Filesharing (AFP) though.

  2. 2008-03-06 at 10:48


    Thanks for the great comment. I know that RAID 0 is a risk, and I don’t normally use it for anything. As I noted in my post, I made the mistake during shuttling data from one place to another, of allowing the only copy of some stuff that was important to me to reside on the USB disks. Of course, Murphy tends to pounce on situations like that, so that’s when the USB disks failed.

    I’ve tried DiskWarrior, and perhaps I gave up to early after letting it grind away for only 36 hours, but according to the Mac’s Console, the system had lost communications with the USB chassis for some reason.

    I recall hearing about Spinrite years ago, but it hadn’t occurred to me now, since this is a Mac-formatted disk, but I didn’t know that Spinrite could handle Mac disks. The stuff that was on it was definitely worth $89 to me, so I’m going to give Spinrite a try by sticking the disks into a PC chassis and using the Spinrite bootable CD.

  3. 2008-03-06 at 18:33


    Yes, SpinRite is OS and filesystem agnostic. It apparently works at the sector level(?) so it works on any disk (PC, Mac, Tivo, etc.), even if encrypted apparently. I’ve not used it myself (haven’t been desperate enough yet :) ) but being a listener of the Security Now podcast, you can’t but help hear about what it can do (Steve Gibson, the co-host, is the also the creator SpinRite).

    Btw, have you tried using ZFS for Mac (http://trac.macosforge.org/projects/zfs/wiki/downloads)? I’m also looking to set up ZFS at home. Using a Mac is my first option, but I’m willing to use a Solaris 10 x86 box, if needed.

    I’ve been able to format a drive and create zpool/zfs datasets using it off one of our Leopard Macs. I haven’t really stress-tested it enough to say it should store our “real” data yet, but looks promising so far.

  4. 2008-03-07 at 14:59

    I haven’t used ZFS on my Mac yet. I have about 40 Terabytes of ZFS storage in production on Solaris boxes, though. It’s awesome.

    At home I’m playing with ZFS on FreeBSD, like I mentioned. It’s not quite as featureful as the Solaris implementation, but considering the great experience I’ve had with FreeBSD for many years, I expect it will prove to be very robust.

  5. 2008-04-10 at 15:17

    You want to use an external, non-USB storage device for your TimeMachine backups? I like using AFP so install netatalk and get that running on your BSD machine, then over on the Mac in a terminal app of your choice:

    defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

    Then your AFP share should show up as a valid TimeMachine target.

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