[dm-devel] training mpath to discern between SCSI errors

[Hannes Reinecke]

On 11/30/2010 11:59 PM, Mike Snitzer wrote:
> On Thu, Nov 18 2010 at 10:11pm -0500,
> Malahal Naineni <malahal at us.ibm.com> wrote:
> 
>> Hannes Reinecke [hare at suse.de] wrote:
>>>> Also (although this might be a bit off topic from your patch),
>>>> can we expand such a distinction to what should be logged?
>>>> Currently, it's difficult to distinguish important SCSI/block errors
>>>> and less important ones in kernel log.
>>>> For example, when I get a link failure on sda, kernel prints something
>>>> like below, regardless of whether the I/O is recovered by multipathing or not:
>>>>   end_request: I/O error, dev sda, sector XXXXX
>>>>
>>> Indeed, when using the above we could be modifying the above
>>> message, eg by
>>>
>>> end_request: transport error, dev sda, sector XXXXX
>>>
>>> or
>>>
>>> end_request: target error, dev sda, sector XXXXX
>>>
>>> which would improve the output noticeable.
>>>
>>>> Setting REQ_QUIET in dm-multipath could mask the message
>>>> but also other important ones in SCSI.
>>>>
>>> Hmm. Not sure about that, but I think the above modifications will
>>> be useful already.
>>>
>>> I'll be sending an updated patch.
>>
>> Hannes, is there an updated version of this patch? It applied fine with
>> Linus git tree with a minor reject! I would like to test an updated
>> version if you have one (the update seems to refer to better logging
>> only, right?).
> 
> Hannes,
> 
> Any chance you've had time to fold your proposed logging changes in and
> rebase this patch?  Could you post that updated patch?
> 
yes, will be following shortly.

> I'd like to help see this patch through to inclussion when 2.6.38 merge
> window opens.  I can help with further review, testing and development.
> 
Ok, thanks.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare at suse.de			      +49 911 74053 688
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