American Megatrends MegaRAID Express 500 - Manual (Page 80)

MegaRAID Express 500 Hardware Guide 66
Device Identification on MegaRAID Express 500
All logical drives on each SCSI bus are identified to the host as ID 0.
Differentiate the drives with Logical Unit Identifiers (LUNs). ID 0 cannot be
used for non-disk devices because they are limited to IDs 1 through 6. The
MegaRAID Express 500 is limited to eight logical drives because LUNs are used
to present logical drives. The SCSI-2 ANSI specification has a limit of eight
LUNs per ID. The SCSI-3 specification increased the number of LUNs to 16. An
example of ID mapping follows.
Example of MegaRAID Express 500 ID Mapping
ID Channel 1
0 A1-1
1 A2-1
2 CD
3 A2-5
4 CD
5 A4-1
6 Optical
7 Reserved
8 A5-2
9 A5-6
10 A6-1
11 A6-4
12 A6-7
13 A7-2
14 A7-5
15 A7-8
As Presented to the Operating System
ID LUN Device ID LUN Device
0 0 Disk (A1-X) 1 0 Scanner
0 1 Disk (A2-X) 2 0 CD
0 2 Disk (A3-X) 3 0 Tape
0 3 Disk (A4-X) 4 0 CD
0 4 Disk (A5-X) 5 0 Tape
0 5 Disk (A6-X) 6 0 Optical
0 6 Disk (A7-X)
0 7 Disk (A8-X)