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

Table Of Contents
Preparing the Host System
3–29HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and
Configuration Guide
3–29
Implementation Notes
Add Snap with Linked WWID - The user has a script that runs every night to create a
snapshot, run a backup to tape from the snapshot, then delete the snapshot. Each time
this is done, a new WWID is allocated. When the operating system runs out of room
for all of these “orphaned” WWIDs, the host system must be rebooted. Therefore the
user decides to update the script such that the “add snap” command reads as follows:
CLI> add snap d2 disk10100 d1 use_parent_wwid.
This results in same WWID being used for the snapshot each night.
Run Clonew - Operates the same as “CLI> run clone” with the exception that clonew
will use the linked WWID associated with the source unit instead of allocating a new
one.
CLI> run clonew
Run Clone - Works the same as v86. In other words a unique WWID is always
allocated to the clone unit.
Clonew of a Snap - The user wants to clone a snap unit without using any more
WWIDs. The clone created from the snap unit will be created using the linked WWID
associated with the snap unit.
Exception: A new WWID will be allocated if the snapshot was created using the
use_parent_wwid switch. Each WWID only has one linked WWID variation. If the
linked WWID is already in use, then a new unique WWID is allocated.
Snap of a Clone - The user want to snapshot a clone without using any more WWIDs,
and issues “CLI> add snap d3 disk10300 d2 use_parent_wwid”. D3, the snapshot unit,
will be created with the linked WWID associated with d2.
Exception: A new WWID will be allocated if the clone was created using the “run
clonew” command. Each WWID only has one linked WWID variation. If the linked
WWID is already in use, then a new unique WWID is allocated.
Manual Clone Creation - The user has his own set of scripts that create clones, and
wants to update them to use linked WWIDs. At some point in the script there will be
an “add unit” command. The switch “parent_wwid=<unit>” must be provided.
For example,
CLI> add unit d2 disk10100 parent_wwid=d1
would create a unit d2 from device disk10100 whose WWID would be the linked
WWID associated with unit d1.
Exception: A new WWID will be allocated if the linked WWID associated with d1 is
already in use (for example, a clone or snapshot is already using the linked WWID).