Re: [PATCH RFC 0/9] [SCSI] Enhanced sense and Unit Attention handling

[Hannes Reinecke <hare@suse.de>]

On 01/28/2013 04:44 PM, Bart Van Assche wrote:
> On 01/28/13 16:05, Jeremy Linton wrote:
>> What I think your looking for is RSCN (Registered State Change
>> notification).
>> Hook that, and then check the name server. This will tell you when
>> ports get
>> added/removed. You can then report luns against lun 0 of all the
>> known target
>> ports. This allows you to transparently detect changes.
>>
>> Otherwise, you run the risk of trapping UA's in the lower level
>> portions of
>> the stack that _REALLY_ need to be propagated to the controlling
>> driver or
>> application.
>
> Thanks for the feedback. Unfortunately sending an RSCN is only
> possible when using Fibre Channel as transport layer. I'm looking
> for a solution that also works with other SCSI transports, e.g.
> iSCSI and SRP.
>
And we're already doing that. Rather, the FC HBAs do exactly this.

So the proposal would be to export a 'virtual' LUN0 if none is 
present, so that we always have a device to talk to, right?

Shouldn't be too hard; we already create a 'virtual' LUN0 during 
scanning, only we delete it if no LUNs are found.
So we're already doing this, only we don't tell :-)

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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