DSM/SCM User's Guide

Configuring DSM/SCM
DSM/SCM User’s Guide — 529846-014
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Configuring a Backup Host System
Configuring a Backup Host System
For disaster recovery, you can configure a backup DSM/SCM host system to function
as the primary host system if your primary host system fails. You cannot manage the
same target from more than one host. To manage a target systems using a different
host system, you must use INITENV to reinitialize the target and specify the new host
system. The software revision histories for the target maintained on the old host
system are lost. To circumvent this, you can maintain a backup host system with
certain volumes and configurations identical to your primary host system. If necessary,
the backup system can relatively easily assume the identity and function of the primary
host.
In this procedure, one NonStop S-series system is configured as the primary host
system, and another as the backup host system. Only the primary host is active in the
DSM/SCM environment and used for all DSM/SCM operations. Use the backup host
only in a non-business critical environment such as for development.
To ensure you always have a backup record of the current state of the DSM/SCM
environment, routinely back up the primary host. For a smooth transfer of DSM/SCM
operations from the primary host to the backup host, the backup must be current. If you
do not backup the primary host after every DSM/SCM operation, problems might arise
from discrepancies between the backup record and the actual state of the DSM/SCM
environment.
If the primary host fails:
1. Bring down the backup system.
2. Bring up the backup system as the primary host, using the primary host’s system
name and number and IP address.
3. Restore the backup t
ape from the primary host onto the backup host.
Caution. One or both of these steps ensure you always have a backup of your system
information:

Running your system with a mirror of $SYSTEM

Creating a backup disk image of $SYSTEM and storing it in a safe place so you can
physically install and boot the backup disk if needed
Caution. Applications previously running on th
e backup host can be ad
versely affected by this
procedure because there are no provisions for recovery of any applications other than
DSM/SCM. For this reason, the backup host should be a noncritical system.