Re: devices get kicked from RAID about once a month

[Bill Davidsen <davidsen@tmr.com>]

Neil Brown wrote:
> On Wed, 02 Jun 2010 20:29:46 +0200
> Stefan /*St0fF*/ Hübner <st0ff@gmx.net> wrote:
>
>   
>>> Any other suggestions?  
>>>       
>> Not really, it's up to Neil to export some sysfs-variable, where you
>> could tune how long a drive may take to respond to some command.
>>
>>     
>
> Nope.  md doesn't do any timeouts.
>   

That's the problem. A timeout between getting the timeout status and 
trying the rewrite is really needed to have any hope of recovery.

If there were a write intent bitmap for the drive, perhaps the drive 
could enter some "may be recovering" state and writes, including the one 
to rewrite the sector, could be help off for some few minutes. I say 
that, knowing that there is at least some similar code working for 
network attached drives, which seem to survive a brief network issue.

Telling the user a write intent bitmap is needed and making use of it 
sound at all practical as a use for some existing code?

> You need to look for, or ask for, such variables at the scsi/sata layer.
>
>   
The need for a delay between timeout and rewrite

-- 
Bill Davidsen <davidsen@tmr.com>
  "We can't solve today's problems by using the same thinking we
   used in creating them." - Einstein


--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html