Spurious reboot in 8.1-RELEASE when reading from ZFS pool with > 9 disks

[Boris Kochergin]

  Ahoy. I just thought I'd add a data point to the mix. I have an 
11-disk v13 pool comprised of 400-GB disks on an 8.1 amd64 system and 
the machine behaves just fine with it:

# zpool status
   pool: archive
  state: ONLINE
status: The pool is formatted using an older on-disk format.  The pool can
         still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'.  Once this is done, the
         pool will no longer be accessible on older software versions.
  scrub: resilver completed after 0h0m with 0 errors on Fri Oct  8 
17:56:52 2010
config:

         NAME        STATE     READ WRITE CKSUM
         archive     ONLINE       0     0     0
           raidz1    ONLINE       0     0     0
             ad4     ONLINE       0     0     0  133K resilvered
             ad6     ONLINE       0     0     0  84K resilvered
             ad8     ONLINE       0     0     0  85.5K resilvered
             ad10    ONLINE       0     0     0  84.5K resilvered
             ad12    ONLINE       0     0     0  88K resilvered
             ad14    ONLINE       0     0     0  83.5K resilvered
             ad16    ONLINE       0     0     0  83K resilvered
             ad18    ONLINE       0     0     0  84.5K resilvered
             ad20    ONLINE       0     0     0  85.5K resilvered
             ad22    ONLINE       0     0     0  84K resilvered
             ad24    ONLINE       0     0     0  86.5K resilvered

errors: No known data errors

-Boris

On 10/20/10 13:26, Sean Thomas Caron wrote:
> Hi Lawrence,
>
> Interesting; have you tried this for raidz2 as well?
>
> I just created a raidz2 pool with 5 disks and then added another 5 
> disk raidz2 to it, so, total of 10 disks in the pool (though this is 
> ultimately a losing strategy unless the number of disks is >> 9 
> because two drives are lost for parity in each sub-raid in the pool).
>
> It (seemed) just slightly more stable than creating a single raidz2 
> pool with > 9 disks but it still crashes.
>
> I guess this does allow me to say its more an issue of number of 
> devices in the pool versus capacity of the pool because with the 
> parity drives taken out, the pool with two 5-disk raidz2s has less 
> total capacity than a pool with a single 9-disk raidz2.
>
> Just out of idle curiousity, I also tried it with raidz1 on my system. 
> Again, I created a 5-disk pool, raidz1 this time, then added another 
> 5-disk raidz1 to the pool for, again, total of 10 disks.
>
> Again, a bit of a losing strategy versus creating one great big raidz 
> unless the number of disks is >> 9 because of losing a disk in each 
> sub-raidz1 in the pool for parity but less so of course than raidz2.
>
> This seemed to crash too, same behavior.
>
> Are you using 8.1-RELEASE or STABLE or ...?
>
> Best,
>
> -Sean
>
>>
>> I have a 16 disk pool, if you create it with
>>
>> zpool create poolname raidz disk1 disk2 disk3 etc
>>
>> then
>>
>> zpool add poolname raidz disk8 disk9 disk10 etc
>>
>> You get the full size pool and no issues.
>>
>>   pool: tank
>>  state: ONLINE
>>  scan: scrub repaired 0 in 0h0m with 0 errors on Wed Oct 20 14:54:08 
>> 2010
>> config:
>>
>>         NAME        STATE     READ WRITE CKSUM
>>         tank        ONLINE       0     0     0
>>           raidz1-0  ONLINE       0     0     0
>>             da0     ONLINE       0     0     0
>>             da1     ONLINE       0     0     0
>>             da2     ONLINE       0     0     0
>>             da3     ONLINE       0     0     0
>>             da4     ONLINE       0     0     0
>>             da5     ONLINE       0     0     0
>>             da6     ONLINE       0     0     0
>>             da7     ONLINE       0     0     0
>>           raidz1-1  ONLINE       0     0     0
>>             da8     ONLINE       0     0     0
>>             da9     ONLINE       0     0     0
>>             da10    ONLINE       0     0     0
>>             da11    ONLINE       0     0     0
>>             da12    ONLINE       0     0     0
>>             da13    ONLINE       0     0     0
>>             da14    ONLINE       0     0     0
>>             da15    ONLINE       0     0     0
>>
>> errors: No known data errors
>>
>
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