Re: training mpath to discern between SCSI errors

On 11/30/2010 11:59 PM, Mike Snitzer wrote:

On Thu, Nov 18 2010 at 10:11pm -0500,
Malahal Naineni [off-list ref] wrote:

quoted

Hannes Reinecke [hare@suse.de] wrote:

quoted

quoted

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.

quoted

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
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