HP 3000 Manuals HP 3000 Manuals
Chapter 1 Introduction
SPU (system processor unit) Switchover/XL is designed to increase data
availability. SPU Switchover/XL enables one SPU to take over processing
for another SPU upon request. This allows processing to continue while a
down or failed SPU is being updated or repaired. It also allows you to
balance the processing load between SPUs.
Scheduled system downtime caused by regular SPU maintenance is reduced.
Whenever the home system needs to be down for an extended period, the
alternate system can be allowed access to data on the home system. The
data can be accessed only by the alternate system by performing a
switchover.
The following are features of the SPU Switchover/XL product:
* Switchover - If the system is down for maintenance, has failed, or
the processing load needs to be balanced, designated switchable
volume sets (nonsystem volume sets designated for switching to the
alternate system) can be switched to the alternate system. This
enables processing to continue.
* Recovery Time - Switchover and application recovery time is no
longer than that associated with a system reboot, and in many
cases is much shorter.
* Operator Intervention - The switchover is done through operator
commands.
* No Reboot - The alternate system does not require rebooting.
* System Equality - The two systems connected for switchover can
have an equal relationship (home and alternate to each other), or
one can be a home system and the other the alternate system.
* Switchback - The switchable volume sets can be switched back to
the home system when it has been updated, or repaired, or load
balancing is no longer required.
NOTE This product is not intended to assist recovery from software
failures.