Re: Error handling on FC devices

[Hannes Reinecke <hare@suse.de>]

On 11/27/2012 09:29 PM, Elliott, Robert (Server Storage) wrote:
> There is a new command in SPC-4 called REMOVE I_T NEXUS that is intended to help
 > that situation.  REMOVE I_T NEXUS lets the application client use 
a good I_T nexus
 > to abort commands that were being processed on a bad I_T nexus, 
so it can safely
 > re-issue those commands on the good I_T nexus without worrying 
that the original
 > commands might resume.
>
> In contrast:
> - the ABORT TASK, ABORT TASK SET, and CLEAR TASK SET must use the same I_T nexus
 >   as the commands being aborted, so are not viable if that I_T 
nexus is bad
> - LOGICAL UNIT RESET aborts commands from every I_T nexus, so in addition to
 >   aborting commands from the bad I_T nexus it also affects 
commands on the
 >   good I_T nexus
>
Hmm. Nice in principle, but the problem here is that we cannot 
guarantee the nexus is still intact.
So one would need to implement this in the HBA firmware; the 
firmware would need to be able to process the TMF, and do the 
appropriate things for the FC stack like dropping the rport etc.

Good idea, though.

James, Andrew, Chad?
Any chance of having a firmware supporting REMOVE IT-NEXUS ?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
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