ZFS 'read-only' device / pool scan / import?

[Karl Pielorz]

--On 20 October 2010 11:35 +0100 Pete French <petefrench at ticketswitch.com> 
wrote:

> You can do a forced export - as long as the system doesnt think
> the pool is imported then an import will go looking. I made a
> similar mess of my drives the first time I changed discs oover, and I
> also didnt know about the import/export trick. But since then I
> have used iit every time I have got into trouble and it has always
> worked for me.

As a follow up to this - we tried to reproduce the original problem once 
we'd restored the data. We removed a drive - rebooted, and got 'a mess':

"
        NAME        STATE     READ WRITE CKSUM
        vol         UNAVAIL      0     0     0  insufficient replicas
          mirror    ONLINE       0     0     0
            da1     ONLINE       0     0     0
            da2     ONLINE       0     0     0
            da3     UNAVAIL      0     0     0  corrupted data
          mirror    UNAVAIL      0     0     0  insufficient replicas
            da4     FAULTED      0     0     0  corrupted data
            da5     FAULTED      0     0     0  corrupted data
            da6     FAULTED      0     0     0  corrupted data
          mirror    UNAVAIL      0     0     0  insufficient replicas
            da7     FAULTED      0     0     0  corrupted data
            da8     FAULTED      0     0     0  corrupted data
            da9     FAULTED      0     0     0  corrupted data
          mirror    UNAVAIL      0     0     0  insufficient replicas
            da10    FAULTED      0     0     0  corrupted data
            da11    FAULTED      0     0     0  corrupted data
"


Doing a zpool export, then a zpool import (which required '-f' to get past 
"cannot import 'vol': pool may be in use from other system use '-f' to 
import anyway")

Seems to have done the trick:

"
        vol         ONLINE
          mirror    ONLINE
            da1     ONLINE
            da2     ONLINE
            da4     ONLINE
          mirror    ONLINE
            da5     ONLINE
            da6     ONLINE
            da7     ONLINE
          mirror    ONLINE
            da8     ONLINE
            da9     ONLINE
            da10    ONLINE
          mirror    ONLINE
            da11    ONLINE
            da12    ONLINE
"

We now just have to re-attach the missing da3 to the last mirror set...

Thanks to all who replied - this has now all been written up in that 
machines notes,

Regards,

-Karl