HSG80 ACS Solution Software Version 8.7 for Compaq OpenVMS Installation and Configuration Guide

Planning a Subsystem

1–14 HSG80 ACS Solution Software Version 8.7 for Compaq OpenVMS Installation and

Configuration Guide

• 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 1–1 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

Using CLI to Specify Identifier for a Unit

The command syntax for setting the identifier for a previously created unit (virtual

disk) follows:

SET UNIT_NUMBER IDENTIFIER=NN

NOTE: For simplicity, StorageWorks recommends that the identifier match the unit number. For

example, to set an identifier of 97 for unit D97, use the following command:

SET D97 IDENTIFIER=97

Table 1–1: Unit Assignments and SCSI_VERSION

SCSI_VERSI

Offset

Unit

Assignment

What the connection sees

LUN 0 as

SCSI-2 Divisible by

At offsets Unit whose number

matches offset

SCSI-3 Divisible by

Not at offsets CCL