Re: [PATCH 2.6.13 5/14] sas-class: sas_discover.c Discover process (end devices)

Andreas Herrmann
2005-09-16T07:29:05Z

On 14.09.2005 07:22 Sergey Panov <sipan@sipan.org> wrote:
> On Tue, 2005-09-13 at 15:25 -0700, Patrick Mansfield wrote:

> > I think the only HBA's today that can handle an 8 byte lun are lpfc
and
> > iscsi (plus new SAS ones).

> I am not aware of any SCSI/FC/SAS/etc hardware which uses more then just
> first two bytes, but all drivers I looked at to proper bytes
> rearrangement for those two bytes, and, as a result they do support 00b
> and 01b addressing modes.

In certain configurations IBM's DS8000 uses 2nd level addressing with
flat space addressing method (01b). Thus ending up with 8 byte LUNs
where the first 4 bytes are really used, e.g. 40:ab:40:cd:00:00:00:00.
This allows to address more than 0x3fff LUNs. But I don't know whether
that many LUNs can be configured in practice.

BTW, zfcp really handles 8 byte LUNs using "unsigned long long" on
big (endian) iron ;-)
(However LUNs have to be configured via sysfs - no LUN scanning
supported at the moment ;-(

Regards,

Andreas