ZFS RaidZ-2 problems

[Paul Wootton]

Hi,

I have had lots of bad luck with SATA drives and have had them fail on 
me far too often. Started with a 3 drive RAIDZ and lost 2 drives at the 
same time. Upgraded to a 6 drive RAIDZ and lost 2 drives with in hours 
of each other and finally had a 9 drive RAIDZ (1 parity) and lost 
another 2 drives (as luck would happen, this time I had a 90% backup on 
another machine so did not loose everything). I finally decided that I 
should switch to a RAIDZ2 (my current setup).
Now I have lost 1 drive and the pack is showing as faulted. I have tried 
exporting and reimporting, but that did not help either.
Is this normal? Has any one got any ideas as to what has happened and why?

The fault this time might be cabling so I might not have lost the data, 
but my understanding was that with RAIDZ-2, you could loose 2 drives and 
still have a working pack.

I do still have the 90% backup of the pool and nothing has really 
changed since that backup, so if someone wants me to try something and 
it blows the pack away, it's not the end of the world.


Cheers
Paul


pool: storage
state: FAULTED
status: One or more devices could not be opened.  There are insufficient
         replicas for the pool to continue functioning.
action: Attach the missing device and online it using 'zpool online'.
    see: http://illumos.org/msg/ZFS-8000-3C
   scan: resilvered 30K in 0h0m with 0 errors on Sun Oct 14 12:52:45 2012
config:

         NAME                      STATE     READ WRITE CKSUM
         storage                   FAULTED      0     0     1
           raidz2-0                FAULTED      0     0     6
             ada0                  ONLINE       0     0     0
             ada1                  ONLINE       0     0     0
             ada2                  ONLINE       0     0     0
             17777811927559723424  UNAVAIL      0     0     0  was /dev/ada3
             ada4                  ONLINE       0     0     0
             ada5                  ONLINE       0     0     0
             ada6                  ONLINE       0     0     0
             ada7                  ONLINE       0     0     0
             ada8                  ONLINE       0     0     0
             ada10p4               ONLINE       0     0     0

root at filekeeper:/storage # zpool export storage
root at filekeeper:/storage # zpool import storage
cannot import 'storage': I/O error
         Destroy and re-create the pool from
         a backup source.

root at filekeeper:/usr/home/paul # uname -a
FreeBSD filekeeper.caspersworld.co.uk 10.0-CURRENT FreeBSD 10.0-CURRENT 
#0 r240967: Thu Sep 27 08:01:24 UTC 2012     
root at filekeeper.caspersworld.co.uk:/usr/obj/usr/src/sys/GENERIC  amd64