HP NonStop G-Series - Manual (Page 62)

Switchovers
ServerNet Nomadic Disk (Release 2) User’s Guide — 523968-001
5 -2
Preparing for a Switchover
After a switchover, operations continue on the backup node following a planned or
unplanned outage of the primary node:
•
A switchover is planned when the primary node is halted to perform significant
maintenance tasks or software upgrades.
•
A switchover is unplanned when a primary node fails.
Preparing for a Switchover
•
Review Logically Switching a Database on page 1-6 and Section 7, Nomadic Disk
Manager Interface . It is strongly recommended that you use the Nomadic Disk
Manager to both physically and logically switch Nomadic volumes. Note that you
must log on as the Super ID (255,255) to use the Nomadic Disk Manager.
•
A backup node must be available to do the processing while the primary node is
unavailable.
•
A backup node is usually located with remotely mirrored disks (for an example of a
dual-path configuration see
Figure 1-1 on page 1-3).
Switchover Examples
The examples in this section show the sequence of events and commands used to
perform a switchover. For more information about the commands used in these
examples:
•
For detailed information about the Nomadic Disk Manager commands, see
Section 7, Nomadic Disk Manager Interface .
•
For information about the switch command interface (SWCI), see Section 6, Switch
Command Interface (SWCI) .
Caution. Detailed information on switching a database without using the Nomadic Disk
Manager is beyond the scope of this manual. If you choose to not use the Nomadic Disk
Manager, the procedures in this section provide only an overview of the process of switching
the Nomadic disks from the primary node to its backup node, and might not be applicable in all
situations.