Multiported disks

Elliott, Robert (Server Storage) elliott at hp.com
Mon Jun 27 08:53:30 PDT 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* "Elliott, Robert (Server Storage)" <elliott at hp.com>
*
> -----Original Message-----
> From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf 
> Of Burn Alting
> Sent: Monday, June 27, 2005 9:57 AM
> To: t10 at t10.org
> Subject: Multiported disks
> 
> I have two question about multiported logical units (eg disks).
> 
> If a logical unit is multiported, then should each of say the 
> T10, EUI64 or NAA identification descriptors be different depending 
> on which port or 'path' the logical unit is accessed via?
> 
> For example, lets say I have a dual ported fibre channel disk.  I
> connect one port to one HBA and the other port to another HBA 
> and issue INQUIRY commands to the disk requesting the device 
> identifier VPD (page 0x83) via both HBA's. Should, say the reported 
> T10 or EUI64 identification descriptors be identical or different?

For the Device Identification VPD page (83h):
* the identifiers with Association=0 (logical unit) or 2 (device) are
supposed to be the same regardless of the target port being used to 
run the INQUIRY command.
* the identifiers with Association=1 (target port) are supposed to 
change based on the target port being used to run the INQUIRY command.

> My second question relates to VPD page code 0x80 (serial number) and a
> multi ported logical unit. Should the serial number for a logical unit
> be the same regardless of the access path? That is, is the 
> serial number of a logical unit bound to the logical unit or the 
> logical unit and port it is accessed via?

The Unit Serial Number VPD page (80h) is "for the SCSI target device or 
logical unit" so it is supposed to be the same regardless of the target 
port being used to run the INQUIRY command.

> Thanks in advance
> 
> Burn

--
Rob Elliott, elliott at hp.com
Hewlett-Packard Industry Standard Server Storage Advanced Technology
https://ecardfile.com/id/RobElliott


 
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