HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and Configuration Guide

Table Of Contents
Preparing the Host System
3–28 HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and
Configuration Guide
Linking WWIDs for Snap and Clone Units
LUN WWIDs (World Wide Identifiers) for snap and clone units are different each
time they are created. This causes more system data records to keep track of the
WWIDs as well as script changes at the customer sites. To eliminate this issue, a
linked WWID scheme has been created, which keeps the WWIDs of these units
constant each time they are created.
The WWID of a LUN is 128bits long, and is composed as follows:
Controller Node ID is the 64-bit fibre channel node id of the controller pair.
Controller Serial is the low-order 48 bits of the controller that “initialized” the storage
set. The Controller_Serial is composed from several fields, but the high order 12 bits
are a Reserved Field.
VSN_Seed is a counter that is incremented every time we initialize a storage set.
If the linked WWID is already in use, a unique WWID is allocated, and a message to
this effect is displayed. This is not a syntax error and does not cause the command to
fail.
CLI format
CLI> add snapshot_units <SnapUnit> <UnitName> <SourceName>
use_parent_wwid
Snapshot Unit - unit number to be assigned to the snap unit.
Unit Name - name of storage set or disk that will become the snap
unit.
Source Name - unit number of source storage set or disk.
Example:
CLI> add snap d2 disk10100 d1 use_parent_wwid
Example of error message text:
CLI> add snap d2 disk10100 d1 use_parent_wwid
A new WWID has been allocated for this unit because the linked WWID for d2 is already in use.
CLI> run clonew
LW3 LW2 LW1 LW0
Controller Node ID Controller Serial VSN_Seed