ZFS question

[George Kontostanos]

On Sat, Feb 18, 2012 at 12:35 PM, Denis Fortin <fortin at acm.org> wrote:
> Good morning,
>
> On a small system using FreeBSD 9.0-RELEASE, ZFS is reporting an issue on a
> pool, that I am not certain is really an issue, but I don't know how to
> investgate...
>
> Here is the situation: I have created a ZFS pool on an external 1TB Maxstor
> USB drive.
>
> The ZFS pool sees little or no activity, I haven't started using it for real
> yet.
>
> The drive spins down frequently because of lack of activity, and takes quite
> a few seconds to spin up.
>
> Now, I frequently get errors in the 'zpool status' thus (like, a couple of
> times per day):
>
>> [denis at datasink] ~> zpool status -v
>>   pool: maxstor
>>  state: ONLINE
>> status: One or more devices has experienced an unrecoverable error.  An
>>         attempt was made to correct the error.  Applications are
>> unaffected.
>> 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 0h0m with 0 errors on Sat Feb 18 08:49:41 2012
>> config:
>>
>>         NAME                                          STATE     READ WRITE
>> CKSUM
>>         maxstor                                       ONLINE       0     0
>>     0
>>           gptid/64a30ca9-56ad-11e1-80c4-000024ce7c30  ONLINE       1     0
>>     0
>>
>> errors: No known data errors
>> [denis at datasink] ~> zpool iostat -v maxstor
>>                                            capacity     operations
>>  bandwidth
>> pool                                    alloc   free   read  write   read
>>  write
>> --------------------------------------  -----  -----  -----  -----  -----
>>  -----
>> maxstor                                 1.10M   928G      0      0    455
>>  1.11K
>>   gptid/64a30ca9-56ad-11e1-80c4-000024ce7c30  1.10M   928G      0      0
>>  455  1.11K
>> --------------------------------------  -----  -----  -----  -----  -----
>>  -----
>
> I know that this sounds bad for the drive, but I cannot find anywhere in my
> logs (/var/log/messages, dmesg, etc) a reference to this supposed
> 'unrecoverable error' that the drive has had, and the resilvering *always*
> works.
>
> I am wondering whether it might not simply be a timeout issue, that is: the
> drive is taking too long to spin up, which causes a timeout and a read error
> to be reported, which then disappears completely once the drive has spun up.
>
> Does anybody have a suggestion about how I could go about investigating this
> issue?  Shouldn't there be a log of the 'unrecoverable error' somewhere?
>
> Thank you all,
>
> Denis
>
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The power management settings put your drive to sleep after some time
of inactivity.

Unfortunately the only way I have found to adjust this is from a
windows pc utility. (You can download it from their website)

To solve the problem you can export the pool when you don't use it and
import it back again. If that is not possible you can schedule a 5
minute cron job to query the status.

Regards
-- 
George Kontostanos
Aicom telecoms ltd
http://www.aisecure.net