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I have a six disk ZFS raidz1 pool and had a recent failure requiring a disk replacement. No problem normally, but this time my server hardware died before I could do the replacement (but after and unrelated to the drive failure as far as I can tell).

I was able to get another machine from a friend to rebuild the system, but in the process of moving my drives over I had to swap their cables around a bunch until I got the right configuration where the remaining 5 good disks were seen as online. This process seems to have generated some checksum errors for the pool/raidz.

I have the 5 remaining drives set up now and a good drive installed and ready to take the place of the drive that died. However, since my pool state is FAULTED I'm unable to do the replacement.

root@zfs:~# zpool replace tank 1298243857915644462 /dev/sdb
cannot open 'tank': pool is unavailable

Is there any way to recover from this error? I would think that having 5 of the 6 drives online would be enough to rebuild the right data, but that doesn't seem to be enough now.

Here's the status log of my pool:

root@zfs:~# zpool status tank
  pool: tank
 state: FAULTED
status: One or more devices could not be used because the label is missing or invalid.
        There are insufficient replicas for the pool to continue functioning.
action: Destroy and re-create the pool from a backup source.
   see: http://zfsonlinux.org/msg/ZFS-8000-5E
  scan: none requested
config:

    NAME                     STATE     READ WRITE CKSUM
    tank                     FAULTED      0     0     1  corrupted data
      raidz1-0               ONLINE       0     0     8
        sdd                  ONLINE       0     0     0
        sdf                  ONLINE       0     0     0
        sdh                  ONLINE       0     0     0
        1298243857915644462  UNAVAIL      0     0     0  was /dev/sdb1
        sde                  ONLINE       0     0     0
        sdg                  ONLINE       0     0     0

Update (10/31): I tried to export and re-import the array a few times over the past week and wasn't successful. First I tried:

zpool import -f -R /tank -N -o readonly=on -F tank

That produced this error immediately:

cannot import 'tank': I/O error
       Destroy and re-create the pool from a backup source.

I added the '-X' option to the above command to try to make it check the transaction log. I let that run for about 48 hours before giving up because it had completely locked up my machine (I was unable to log in locally or via the network).

Now I'm trying a simple zpool import tank command and that seems to run for a while with no output. I'll leave it running overnight to see if it outputs anything.

Update (11/1): zpool import tank has been running for about 12 hours now with no command line output so far. However, my computer is still responsive so that's a plus.

share|improve this question
    
Is this pool imported or not? I'm guessing not, based on the output from your zpool replace (which I believe only can be run on an imported pool, or at least, I've never tried it on one not imported). You are correct to assume this SHOULD be recoverable. You've got a raidz1 with one faulty disk and at least per that status, no problems on other devices. However the pool level itself is claiming a 'corrupted data' error. I'm curious what 'zpool import tank' says? –  Nex7 Oct 31 '13 at 6:53
    
Thanks for your suggestion Nex7, I had tried a few import commands over the past week and didn't have any luck. I updated my answer above with the details. –  nickv2002 Nov 1 '13 at 5:59
    
How often did you scrub the array? I've got the feeling you're going to say 'never', and you had undetected errors when the disk died, meaning the array is pretty well dead now. SysAdmin1138 has an excellent blog post on the topic if you're unfamiliar. –  Chris S Nov 1 '13 at 17:57
    
I scrubbed the array about a month or so back. Certainly not never. –  nickv2002 Nov 1 '13 at 21:15
    
Quite concerning that zpool import is just sitting there for hours. That shouldn't happen. Can you try grabbing a live CD or USB bootable image of some fairly new illumos-derivative (OmniOS, OpenIndiana, etc) and see if it can import the pool? The code there is newer than what's in ZoL, AFAIK, so it MIGHT have more success. If not, I suspect your only options are limited to data recovery (very expensive, $100's/hr) or destroy the pool and recreate from backups. Try an OmniOS or OI install/liveCD to import it, first, though. –  Nex7 Nov 1 '13 at 23:33
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