Re: hdaprm -Y /dev/sda /dev/sdb -> I/O error -> disk kicked out of RAID - is it normal?

[Tejun Heo <tj@kernel.org>]

NeilBrown wrote:
> On Fri, July 17, 2009 2:12 pm, Tejun Heo wrote:
>> Tomasz Chmielewski wrote:
>>> And one of the disks is kicked out of RAID.
>>>
>>> Is it expected behaviour (although probably the error happens somewhere
>>> in the ata layer)?
>> Yes, it's expected.  Wakeup requires reset via EH and md requests have
>> FAILFAST flag set, so they never get retried.  The behavior can be
>> changed tho.  Hmmm... not entirely sure what to do at this point.
> 
> Nope, 'md' requests do not get FAILFAST set.

Oh... then it's unexpected.  I'll see if I can reproduce the failure
here.

> I tried that and easily found cases where it fails way too fast.
> FAILFAST seems to mean different things on different devices, making
> it useless in general (it is still useful in some specific cases
> such as multipath on devices which are expected to be used under
> multipath and so treat FAILFAST appropriately).

Yeap, FAILFAST flags seem geared pretty much toward multipathing.

Thanks.

-- 
tejun