ServerNet Cluster Manual

Managing a ServerNet Cluster
ServerNet Cluster Manual—520575-003
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Switching the SNETMON or SANMAN Primary and
Backup Processes
5. On remote systems, as the ServerNet cluster monitor processes receive word that
a ServerNet cluster member has departed, they instruct their local processors to
bring down the ServerNet connections with the departing system. These remote
ServerNet cluster monitor processes then log the node disconnection to the event
log.
To fully terminate ServerNet cluster services on a system and stop the ServerNet
cluster monitor process, you must issue two SCF commands:
> STOP SUBSYS $ZZSCL
> ABORT PROCESS $ZZKRN.#ZZSCL
Stopping the ServerNet cluster monitor process by using an SCF ABORT PROCESS
$ZZKRN.#ZZSCL command alone terminates the $ZZSCL process, but does not bring
down ServerNet cluster services on the local system.
If you use only the SCF ABORT PROCESS command, the system remains joined to
the ServerNet cluster for up to 30 seconds if the ServerNet cluster state for the node is
STARTED (as represented by the SUBSYS $ZZSCL object for the node). After 30
seconds, the Expand-over-ServerNet line-handlers, which periodically exchange status
messages with the local ServerNet cluster monitor process, terminates the Expand-
over-ServerNet connections.
Switching the SNETMON or SANMAN Primary and Backup
Processes
You can use the TSM Service Application or SCF to cause either the SNETMON or
SANMAN primary and backup processes to switch roles. For example, if the primary
process is configured to run in processor 0 and the backup process is configured to run
in processor 1, you can use the TSM Switch SNETMON Primary Processor action
(or the Switch SANMAN Primary Processor action) to switch the primary to
processor 1 and the backup to processor 0.
Switching SNETMON is recommended if you need to halt a processor. You might need
to halt a processor, for example, to prepare for reloading the processor or servicing a
PMF CRU.
Using TSM to Switch the Primary and Backup Processes
Use the following procedure to switch the primary and backup processes using the
TSM Service Application:
1. Log on to the TSM Service Application, as described in Appendix F, Common
System Operations. The Management Window appears.
2. Click the Cluster tab. See Figure 5-4 on page 5-4.
Note. Normally, you should not need to abort SNETMON—even if a system is no longer a
member of a ServerNet cluster.