Unit Numbering Examples - Compaq StorageWorks HSZ80 Configuration And Cli Reference Manual

The first character is a letter indicating the kind of device in the storage unit: use
D for disk devices or P to indicate passthrough devices such as tape devices,
loaders, and libraries.
If entered, the next one or two digits indicate which target ID number is to access
the unit during normal operation. Use one of the controller's SCSI target ID
numbers assigned to the controller with the SET controller ID command. Omit
leading zeroes for SCSI target ID numbers less than ten. For example, use 2
instead of 02 for a storageset being accessed through the controller SCSI target
ID number 0, LUN 2. The SCSI target ID number is initially set with the SET
controller PORT_1_ID (or PORT_2) command. See 5–91 for an explanation of
the SET controller commands.
By carefully choosing the SCSI target ID number when adding units, the pre-
ferred paths for all of your storage units in a dual-redundant configuration can be
established. Data I/O load to the units can likewise be controlled by equally dis-
tributing unit access between the controllers.
NOTE: When operating in multiple bus failover mode, settings specified with the
PORT_1_PREFERRED_ID (or PORT_2) switch takes priority over settings assigned
with the SET controller PORT_1_ID (or PORT_2) switch.
The digit following the SCSI target ID number is always zero.
The last digit identifies the logical unit number (LUN) for the device or storage
unit. Acceptable LUN numbers are 0 through 31, depending on your operating
system.
Table 5–2 Unit Numbering Examples
Unit Number Device Type
D1207 disk
D401 disk
D39
D5 disk
Compaq HSZ80 Array Controller ACS Version 8.3 Configuration and CLI Reference Guide
Target ID Number
12
4
(not an acceptable unit number)
0
5–5
LUN
7
1
5