Report LUNs if more than 256 LUNs on the same bus
Gerry.Houlder at seagate.com
Gerry.Houlder at seagate.com
Tue Apr 1 07:32:08 PDT 2008
* From the T10 Reflector (t10 at t10.org), posted by:
* Gerry.Houlder at seagate.com
There are some options on this. Please refer to SAM-4, clause 4.7 for a
full description on this. My opinions listed here:
(a) You could use peripheral device addressing method, where 2 most
significant bits of byte 0 are set to 00 binary. This groups the LUNs on
different buses (6 bits of byte 0 consists of a bus identifier) with up to
256 LUNs per bus. The effective address space for this is
00 00 00 00 00 00 00 00 through 3F FF 00 00 00 00 00 00.
(b) You could use the flat space addressing method, where the 2 MS bits of
byte 0 are set to 01 binary.
This gives LUNs 40 00 00 00 00 00 00 00 through 7F FF 00 00 00 00 00 00.
If this isn't enough for you, you need to use the multilevel structure
defined later in the clause. If you need that much space, you definitely
need to read SAM-4.
<Marian_Lakov at us.
Sent by: <t10 at t10.org>
owner-t10 at t10.org cc
No Phone Info
Report LUNs if more than 256 LUNs
on the same bus
If a RAID controller presents more than 256 LUNs to a host on the same bus
what is the proper LUN format?
00 00 00 00 00 00 00 00 to 00 00 00 00 00 00 00 FF for the LUNs 0 to 255
40 00 00 00 00 00 01 00 to 40 00 00 00 00 00 3F FF for the LUNs above 255
40 00 00 00 00 00 00 00 to 40 00 00 00 00 00 3F FF for all the LUNs
Also, for the LUNs above 255, is it possible to use 00 00 00 00 00 00 01 00
to 00 00 00 00 00 003F FF format?
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