RE: iSCSI: problem with LUN discovery

["Douglas Otis" <dotis@sanlight.net>]

Nelson,

A lot happens before you get to the problem of sorting targets and LUNs.  If
you receive the parameters during an authorization process which allows
access in the first place, then the only step left is to verify settings.
It should not be a problem of discovery but of verification.  Anything
unique could be used not alterable by the client to check against the
settings.  These settings should be in a redundant database partially shared
between the client and SCSI portal.

Doug

>
> The question is if a storage controller keeps a different GUID
> for every LUN
> created. If not we are in the same problem as WWN, LUN naming.
> The question is how to identify a LUN in a storage controller that can
> create and delete thousands of LUNs, and that the same WWN, LUN
> combination
> can address different volumes depend on the intiator.
> Also to keep this identifier in the EEPROM of the controller is not a good
> idea, as cause problems when the controller is replaced.
>
> I think that the best way is to identify a LUN by a string composed by a
> <GUID> (or S/N) <date> and <time> of the LUN creation. This
> method allows to
> create infinite LUNs (over the time) in a given controller.
> Keeping this string in the media and presented it in a Inquiry page avoids
> the identification problems in controllers with multiple channels, that
> supports different mapping for multiple initiators.
>
> Nelson Nahum
> StoreAge
>
> ----- Original Message -----
> From: Y P Cheng <ycheng@advansys.com>
> To: Nelson Nahum <NNahum@store-age.com>; 'John Muth' <muth@veritas.com>;
> <ips@ece.cmu.edu>
> Sent: Wednesday, October 04, 2000 9:01 PM
> Subject: RE: iSCSI: problem with LUN discovery
>
>
> > > -----Original Message-----
> > > From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
> > > Nelson Nahum
> > >
> > > The problem is that the signature written by the VxVM is not standard
> and
> > > only is recognized by the Veritas VxVM.
> > > Due to the fact that the important thing is to identify the media not
> the
> > > controller (as Veritas does), the best way is to have the
> serial number
> > > written in the media in a non accessible sector, and loaded by the
> > > controller to one of the Inquiry pages of the LU. In this manner no
> matter
> > > which channel, WWN, LUN  the specific LUN is presented can be
> > > recognized by every initiator.
> >
> > Every 1394 and Fibre Channel node, including disk drives, has a GUID,
> Global
> > Unique ID. They are saved in EEPROM by manufacturers.  I
> believe T10 also
> > has a mechanism to report a unique name of a device using mode select.
> > (Page 83h? Someone help!)  iSCSI should make sure that each device has a
> > GUID available by mode select for the initiators.  No need to reinvent
> > another mechanism.
> >
> >
> > Y.P. Cheng, CTO, ConnectCom Solutions Corp.
>