HP StorageWorks HSG80 ACS Solution Software V8.8 for OpenVMS Installation and Configuration Guide (AA-RV1PA-TE, March 2005)

Planning a Subsystem
38 HSG80 ACS Solution Software V8.8 for OpenVMS Installation and Configuration Guide
LUN 2 - unit 22, etc.
In this example, if a unit 20 is defined, it will be superseded by the CCL and
invisible to the connection.
Assigning Host Connection Offsets and Unit Numbers in SCSI-2 Mode
Some operating systems expect or require a disk unit to be at LUN 0. In this case,
it is necessary to specify SCSI-2 mode.
If SCSI_VERSION is set to SCSI-2 mode, the CCL floats, moving to the first
available LUN location, depending on the configuration.
StorageWorks recommends to use the following conventions when assigning host
connection offsets and unit numbers in SCSI-2 mode:
■ Offsets should be divisible by 10 (for consistency and simplicity).
■ Unit numbers should be assigned at connection offsets (so that every host
connection has a unit presented at LUN 0).
Table 3 summarizes the recommendations for unit assignments based on the
SCSI_VERSION switch.
Assigning Unit Identifiers
When configuring storage units, a unique identifier must be specified for each unit
and this identifier must be unique in the cluster.
This section gives two examples of setting an identifier for a previously created
unit: one using CLI and one using SWCC. The CLI uses the older terms
“identifier” and “unit”, while SWCC uses the terms “LUN ID alias” and “virtual
disk”.
Identifier = LUN ID alias
Unit = virtual disk
Table 3: Unit Assignments and SCSI_VERSION
SCSI_VERSION Offset
Unit
Assignment
What the connection
sees LUN 0 as
SCSI-2 Divisible by 10 At offsets Unit whose number
matches offset
SCSI-3 Divisible by 10 Not at offsets CCL