This diskfailure should not panic a system, but just disconnect disk from ZFS

[Michelle Sullivan]

Quartz wrote:
> Also:
>
>> And thus I'd would have expected that ZFS would disconnect /dev/da0 and
>> then switch to DEGRADED state and continue, letting the operator fix the
>> broken disk.
>
>> Next question to answer is why this WD RED on:
>
>> got hung, and nothing for this shows in SMART....
>
> You have a raidz2, which means THREE disks need to go down before the
> pool is unwritable. The problem is most likely your controller or
> power supply, not your disks.
>
Never make such assumptions...

I have worked in a professional environment where 9 of 12 disks failed
within 24 hours of each other....  They were all supposed to be from
different batches but due to an error they came from the same batch and
the environment was so tightly controlled and the work-load was so
similar that MTBF was almost identical on all 11 disks in the array...
the only disk that lasted more than 2 weeks over the failure was the
hotspare...!

-- 
Michelle Sullivan
http://www.mhix.org/