Re: iSCSI: 2.2.6. Naming & mapping

[Pierre Labat <pierre_labat@hp.com>]

John Hufferd/San Jose/IBM wrote:

> 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.

I agree.

> There maybe additional Database (LDAP) processes and
> information that attempts to relate LU #3 known to Host xyz to some name
> "abcd...." etc.

I don't want so much, i would want just to have a unique identifier per LU.
It doesn't cost a lot and it will have the advantages described in the first
mail below.

> 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.
>

Yes, it is not a transport issue, but why not request that now before people
start
building iSCSI controllers if it simplifies the life of everybody?
I don't know how FC managed to have their WWN but why could not we
do the same thing?

Regards,

Pierre

>
> .
> .
> .
> 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