ServerNet Cluster 6780 Operations Guide (G06.28+, H06.05+)

Controlling ServerNet Cluster Processes

ServerNet Cluster 6780 Operations Guide—525606-003

2-7

When a System Joins a ServerNet Cluster

These steps describe what happens when a system joins a ServerNet cluster:

1. The ServerNet cluster monitor process is started (by the $ZPM persistence

manager or with an SCF START PROCESS command, depending on the

STARTMODE configuration).

2. The ServerNet cluster monitor process checks the configuration of its associated

ServerNet cluster (SCL) subsystem SUBSYS object:

•

If the SUBSYS object is configured with a STARTSTATE attribute set to

STOPPED—which is the default—the ServerNet cluster monitor process waits

for an SCF START SUBSYS $ZZSCL command before starting ServerNet

cluster services and joining the system to the ServerNet cluster.

•

If the SUBSYS object is configured with a STARTSTATE attribute set to

STARTED, the ServerNet cluster monitor process automatically starts

ServerNet cluster services and joins the system to the ServerNet cluster.

3. Once ServerNet cluster services on the local system are started, the ServerNet

cluster monitor process establishes ServerNet connections with all other systems

in the ServerNet cluster that are in the STARTED or STARTING states.

4. If the Expand-over-ServerNet line-handler processes are configured and are in the

STARTED state, Expand-over-ServerNet connectivity with the other systems in the

ServerNet cluster is established.

5. When the ServerNet cluster startup is completed, the ServerNet cluster monitor

process has a list of all systems known to be in the ServerNet cluster, and

ServerNet connections are established with each system.

6. If ServerNet connection attempts fail or if successful connections subsequently fail,

periodic attempts are made to establish or reestablish the connection. Failures and

successful reconnections are logged to the event log. Failures to connect are

logged as path or other failures. In addition, each ServerNet Cluster subsystem

state change (to STARTING and then to STARTED) is logged. If no other systems

are discovered, that fact is also logged.

Note. For detailed information about the summary states for the SCL subsystem SUBSYS

object and the STARTSTATE attribute, see Section 4, SCF Commands for SNETMON and

the ServerNet Cluster Subsystem.

Do not confuse the PROCESS object STARTMODE attribute with the SUBSYS object

STARTSTATE attribute:

•

The STARTMODE attribute controls the way the $ZPM persistence manager starts the

ServerNet cluster monitor process after a system load.

•

The STARTSTATE attribute controls the way the ServerNet cluster monitor process

joins the system to the ServerNet cluster.