Hi Rich,

I don't think anyone can say definitively how this problem resolved,
but I believe that the dd command overwrote some of the disk label,
as you describe below.

Your format output below looks like you relabeled the disk and maybe
that was enough to resolve this problem.

I have had success with just relabeling the disk in an active pool,
when I accidentally trampled it with the wrong command.

You could try to use zpool clear to clear the DEGRADED device.
Possibly, scrub again and clear as needed.



On 07/12/12 08:33, RichTea wrote:
 >How did you decide it is okay and that zfs saved you? Did you
 >NOT post some further progress in your recovery?

I made no further recovery attempts,  the pool imported cleanly after
rebooting, or so i thought [1] as a zpool status showed no errors and i
could read data from the drive again.

On Thu, Jul 12, 2012 at 2:35 PM, Edward Ned Harvey
<mailto:opensolarisisdeadlongliveopensola...@nedharvey.com>> wrote:

     > From: zfs-discuss-boun...@opensolaris.org
    <mailto:zfs-discuss-boun...@opensolaris.org> [mailto:zfs-discuss-
     > boun...@opensolaris.org <mailto:boun...@opensolaris.org>] On
    Behalf Of Jim Klimov
     > Purely speculating, I might however suggest that your disk was
     > dedicated to the pool completely, so its last blocks contain
     > spare uberblocks (zpool labels) and that might help ZFS detect
     > and import the pool -

    Certain types of data have multiple copies on disk.  I have
    overwritten the
    first 1MB of a disk before, and then still been able to import the
    pool, so
    I suspect, with a little effort, you'll be able to import your pool

    After the pool is imported, of course, some of your data is very
    likely to
    be corrupt.  ZFS should be able to detect it, because the checksum won't
    match.  You should run a scrub.

[1]  Ok i have run a scrub on the pool and is now being reported as
being in DEGRADED status again.

I did think it was strange that the zpool had magically recovered its self:

root@n36l:~# zpool status data2
   pool: data2
  state: DEGRADED
status: One or more devices has experienced an unrecoverable error.  An
         attempt was made to correct the error.  Applications are
action: Determine if the device needs to be replaced, and clear the errors
         using 'zpool clear' or replace the device with 'zpool replace'.
    see: http://www.sun.com/msg/ZFS-8000-9P
   scan: scrub repaired 0 in 0h26m with 0 errors on Thu Jul 12 15:07:47 2012

         NAME        STATE     READ WRITE CKSUM
         data2       DEGRADED     0     0     0
           c2t0d0s0  DEGRADED     0     0     0  too many errors

errors: No known data errors

At least it is letting me access data for now, i guess the only fix is
to migrate data off and then "rebuild" the disk.


    You'll be able to produce a list of all the partially-corrupted
    files.  Most
    likely, you'll just want to rm those files, and then you'll know you
    good files, whatever is still left.

zfs-discuss mailing list
zfs-discuss mailing list

Reply via email to