RE: iSCSI: INQUIRY page 0x83 identifier

[Michael Krause <krause@cup.hp.com>]

At 01:30 PM 1/26/2001 -0800, Robert Snively wrote:
> > As for an iSCSI type or format for logical unit identifiers:
> > 1) SCSI already allows for an ascii formatted identifier (typically this
> > includes vendor, model, serial number). Since NDT has defined WWUIs for
> > DEVICES and these have a defined UTF-8 format, there is nothing to
> > *prevent* a vendor from using these strings as the starting point for LU
> > page 83 identifiers of the logical units within that device.
> > 2) But..., iSCSI and NDT should not attempt to make a rule under which
> > these are used.  FC's intervention in this was more as a strong suggestion,
> > and is certainly not a requirement.
>
>Jim,
>
>I generally agree with the text of your comments, but there are
>a couple of details I would like to address.
>
>Any name not based on a registered entity and in a registered format
>is not guaranteed to be world-wide unique, and is therefore
>inappropriate.  That is why numbers like OUIs and SCSI Vendor IDs
>in specified parts of the identifier are a requirement.  EUI-64
>and FC identifiers have that property.  FC identifiers have the added
>benefit of having a regular extension capability for dynamic creation
>of logical units.  As you point out, iSCSI need not use FC
>identifiers, but a bunch of people like them for their constant
>defined length and guaranteed world-wide unique identifiers.
>
>However, I feel that iSCSI should be a lot more hard nosed than
>SAM-2 and require that VPD page "83" contain a mandatory world-wide
>unique logical unit identifier in an appropriate invariant format.
>For compatibility with other SCSI drivers, it should be limited
>to 128 bits of length.  This would not be an identifier set by
>the user (there are other SCSI identifiers that can be set by the
>user), but one that is invariant from the time of manufacture (for
>physical devices) or creation (for logical devices) of the logical unit.

Why not just require EUI-64 which is a very large name space and is / will 
be used in many hardware solutions today / future?  This would also fit in 
well with other I/O standards that use EUI-64 for identifying all I/O 
components / controllers.  Having a 128-bit value seems like overkill and 
provides little benefit.

Mike