Re: iSCSI: 2.2.6. Naming & mapping

["John Hufferd/San Jose/IBM" <hufferd@us.ibm.com>]

Folks,
We are again mixing issues and layers again.

There is NO SUCH THING as an iSCSI LU.  There is an iSCSI device which is a
Controller which will have a SCSI layer which in turn supports an LU.  Once
the iSCSI session is established, the Rules of SCSI define how the LUs are
addressed.  There maybe additional Database (LDAP) processes and
information that attempts to relate LU #3 known to Host xyz to some name
"abcd...." etc.  But that is NOT an iSCSI Transport Protocol.  We may need
to work on this at some point but it is not an iSCSI transport issue.

.
.
.
John L. Hufferd


Pierre Labat <pierre_labat@hp.com>@ece.cmu.edu on 09/14/2000 10:06:54 AM

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


To:   ips@ece.cmu.edu
cc:
Subject:  Re: iSCSI: 2.2.6. Naming & mapping



julian_satran@il.ibm.com wrote:

> Not again (what is the sign for frustration?)... I mean not before the
next
> version.
>
> Julo
>
> Raghavendra Rao <Jp.Raghavendra@EBay.Sun.COM> on 14/09/2000 21:04:02
>
> Please respond to Raghavendra Rao <Jp.Raghavendra@EBay.Sun.COM>
>
> To:   Julian Satran/Haifa/IBM@IBMIL
> cc:
> Subject:  iSCSI: 2.2.6. Naming & mapping
>
> I feel that a LUN should be very much part of the Naming scheme
> that has been proposed in the draft, regardless of the level of
> enforcement of the scheme by implementors. LUNs are very much
> part of SCSI addressing, and where LUN doesn't exist, zero is
> assumed.
>
> Without a LUN identifier, Naming section doesn't look complete.
>
> Do you have insights why it is omitted ? Is this by design or overlook ?
>
> Thanks.
> -JP

About the topic of naming a LU, what seems to be  a benefit for me, is to
adopt the same requirement as fibre channel: each LU MUST provide a
unique identifier (from the Device Identification Page).
From what i read it seems that it is not a big deal to add this page in a
LU.
However, this unique identifier is not needed for iSCSI protocol to work.
It doesn't interact with the protocol.

But from an administration point of view, to configure a server using
storage
through iSCSI, the existence of this unique identifier helps a lot.
It allows the configuration product to know/check  if various LUNs
correspond
to the same LU, it could help to manage  the  LU migration (the LUN is
changed

inside a target for the same LU).
It simplifies the configuration software by avoiding it to fake a unique LU
identifier.
It will help in having a configuration tool for iSCSI that can be closer to
the one
used with FC.

Is somebody knowing if it is planned to incorporate this Device
Identification
Page
in the iSCSI LU? Will it be mandatory? Which format (identifier type) will
be
used?
FC  uses the type 3 (FC_PH Name_Identifier).

Regards,

Pierre