RE: iSCSI: Creation of new LUNs (and AENs)

["Jim Hafner/Almaden/IBM" <hafner@almaden.ibm.com>]

Folks,
Whenever anybody suggests AEN, I always want to ask the question:

      To what initiator or initiators does a target send an AEN?

The target shouldn't "broadcast" this sort of thing.  It has to be more
picky about it, *especially* in this networked world.  So, if you suggest
AEN for anything, you have to answer (and spec the answer) to this
question.

Creating new LUs has already been spec'd.  If LU inventory changes for any
reason, a REPORTED LUNS DATA HAS CHANGED unit attention condition is set
up. See SPC-2, rev18, page 141 in the REPORT LUNS command section.  (I
might agree that this isn't necessarily completely sufficient, but it does
address the issue in most cases.  But I don't think iSCSI needs to get
involved in this issue.)

Jim Hafner


Black_David@emc.com@ece.cmu.edu on 09-14-2000 07:04:46 PM

Sent by:  owner-ips@ece.cmu.edu


To:   Julian Satran/Haifa/IBM@IBMIL, ips@ece.cmu.edu
cc:
Subject:  RE: iSCSI: Creation of new LUNs



This sort of proposal should go to T10.  A potential
issue is that not all SCSI transports support
Asynchronous Event Notification (AEN).  iSCSI could
make AEN mandatory to implement as part of addressing
this situation, but standardizing the use of AEN to
report LUN addition needs to be addressed in T10.
An I-D summarizing the problem and proposed solution
without reference to iSCSI or any other transport
might be a good start on this.

--David

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> -----Original Message-----
> From:   julian_satran@il.ibm.com [SMTP:julian_satran@il.ibm.com]
> Sent:   Thursday, September 14, 2000 10:13 AM
> To:     ips@ece.cmu.edu
> Subject:     Re: iSCSI: Creation of new LUNs
>
>
>
> Is somebody else doing it differently?
>
> Julo
>
> Raghavendra Rao <Jp.Raghavendra@EBay.Sun.COM> on 14/09/2000 21:19:58
>
> Please respond to Raghavendra Rao <Jp.Raghavendra@EBay.Sun.COM>
>
> To:   Julian Satran/Haifa/IBM@IBMIL
> cc:
> Subject:  iSCSI: Creation of new LUNs
>
>
>
>
>
> What is the recommended/approved way of announcing the availability
> of new LUNs in the target ? Currently I can do the following, but if
> it isn't explicitly documented, implementors tend to do their own
> things (causing interoperability problems)
>
> Upon creation/deletion of a LUN in the target, a target shall generate
> an asynchronous notification with  the SCSI event indicator set to
> either 2 or 4, followed by sense data with appropriate ASC and ASCQ
> indicating that LUNs have changed. The initiator, on receipt of this
> notification will issue a REPORT_LUN command to get a list of LUNs.
>
> -JP
>