On 01/24/2013 03:38 PM, Bart Van Assche wrote:
On Thu, Jan 24, 2013 at 4:38 AM, Hannes Reinecke <hare@xxxxxxx> wrote:
As for AEN, does iSCSI _do_ AEN? I thought it got removed ...
If it does, though, it should schedule an event on its own whenever an AER
is received. The same goes for LLDDs with vendor-specific AENs; thinking of
megaraid_sas here ...
Let me ask this another way. SAN users expect that the LUN list at the
initiator side gets updated automatically after a SAN configuration
change. How should a SAN system communicate to a SCSI initiator that
the LUN list has been changed ? Some FC SAN systems send a LIP after a
configuration change to force the initiator to rescan LUNs.
And thereby disrupting traffic on _ALL_ LUNs on the loop.
Really cool idea.
I know; the one vendor which does _not_ talk to us.
But how to inform the initiator about a LUN change for other SCSI protocols ?
> I'm not sure that it is even possible to report such a change via
sense
data in case a SAN user first removes all LUNs and after that change
adds one or more LUNs.
The official way is indeed via UAs; most storage arrays (Hello,
NetApp!) provide a default LUN0 which is always visible.
Up to the point that some even refuse to add 'normal' disk LUNs to
LUN0. Or have the ominous 'Well-known Address' LUN to handle these
kind of issues.
Obviously, one needs to send commands to it to even _get_ an UA back.
But yeah, normally it's possible.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@xxxxxxx +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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