ServerNet Cluster 6780 Operations Guide (G06.24+, H06.03+)

Troubleshooting and Replacement Procedures
ServerNet Cluster 6780 Operations Guide—525606-002
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Methods for Repairing ServerNet Connectivity
Problems
Switching the SNETMON Primary and Backup Processes
The SCF PRIMARY PROCESS $ZZSCL command forces a takeover of the
SNETMON primary process. The backup process, upon becoming the new primary,
queries all processors in the node to find the state of ServerNet connections to all other
nodes. If it finds any connections that are down, it initiates a sequence to bring the
connections to an online state.
Using the SCF START SERVERNET Command
The SCF START SERVERNET $ZSNET.fabric.cpu command provides a
noninvasive manual method for recovering ServerNet paths. The SCF START
SERVERNET \remotenode.$ZSNET.fabric.* command is recommended for
speeding up automatic interprocessor communication after a cluster switch hard reset.
The processor that receives the command always checks and brings up any remote
IPC paths that are down on the fabric, regardless of whether the fabric is down or up at
the processor when the command is received.
Stopping and Starting the ServerNet Cluster Subsystem
You can also use this SCF command sequence to repair connectivity problems:
-> STOP SUBSYS $ZZSCL
-> START SUBSYS $ZZSCL
This sequence of commands does not result in a takeover. The primary and backup
SNETMON processes continue to run on their respective processors.
Stopping and starting ServerNet cluster services to repair connectivity problems is less
preferable than using SCF PRIMARY PROCESS $ZZSCL. The SCF STOP SUBSYS
$ZZSCL command stops ServerNet cluster services. The SNETMON process pair
continues to run, but it brings down all ServerNet connectivity between the node on
which the command is issued and all other nodes in the cluster.
The SCF START SUBSYS $ZZSCL command brings up ServerNet cluster connectivity
from scratch. The final effect is that connectivity comes up after this sequence of
commands. However, connectivity was fully brought down before being brought up
again.