Re: MD/RAID time out writing superblock

[Andrei Tanas <andrei@tanas.ca>]

>>>> The drive might take a longer time like this when doing error handling
>>>> (sector remapping, etc), but then I would expect to see your remapped
>>>> sector count grow.
>>>
>>> Yes, this is a possibility and according to the spec, libata EH should
>>> be retrying flushes a few times before giving up but I'm not sure
>>> whether keeping retrying for several minutes is a good idea either.
>>> Is it?
>> ..
>> 
>> Libata will retry only when the FLUSH returns an error,
>> and the next FLUSH will continue after the point where
>> the first attempt failed.
>> 
>> But if the drive can still auto-relocate sectors, then the
>> first FLUSH won't actually fail.. it will simply take longer
>> than normal.
>> 
>> A couple of those, and we're into the tens of seconds range
>> for time.
>> 
>> Still, it would be good to actually produce an error like that
>> to examine under controlled circumstances.
>> 
>> Hmm.. I had a drive here that gave symptoms like that.
>> Eventually, I discovered that drive had run out of relocatable
>> sectors, too.  Mmm.. I'll see if I can get it back (loaned it out)
>> and perhaps we can recreate this specific scenario on it..
> ..
> 
> I checked today, and that drive is no longer available.

Mine errored out again with exactly the same symptoms, this time after only
few days and with the "tunable" set to 2 sec. I got a warranty replacement
but haven't shipped this one yet. Let me know if you want it.