ServerNet Cluster Manual

Troubleshooting and Replacement Procedures
ServerNet Cluster Manual—520575-003
7-24
Methods for Repairing ServerNet Connectivity
Problems
The SCF PRIMARY PROCESS $ZZSMN command is a noninvasive command and is
the recommended command to repair ServerNet connectivity. It does not cause the
SANMAN process to stop running, and it does not cause any ServerNet connectivity
that is already up to go down. It does repair any ServerNet connectivity that is down,
except for cases in which connectivity is down because of ServerNet hardware failures.
Using the SCF START SERVERNET Command to Repair
Connectivity Problems
For servers running the G06.12 RVU, the SCF START SERVERNET
$ZSNET.fabric.cpu command provides a noninvasive manual method for recovering
ServerNet paths. SCF START SERVERNET \remotenode.$ZSNET.fabric.* is the
recommended command for speeding up automatic interprocessor communication
after a cluster switch hard reset.
Previously, this command had no effect if the fabric or local path was already up. At
G06.12, the message system behavior in response to this command was changed so
that the processor that receives the command always checks and brings up any
remote IPC paths that are down on the fabric. This is done regardless of the fabric
being down or up at the processor when the command is received.
Stopping and Starting the ServerNet Cluster Subsystem to
Repair Connectivity Problems
You can also use the following SCF command sequence to repair connectivity
problems:
SCF STOP SUBSYS $ZZSCL
SCF START SUBSYS $ZZSCL
This sequence of commands doesn’t 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. This is because the SCF
STOP SUBSYS $ZZSCL command stops ServerNet cluster services. The SNETMON
process pair continues to run, but it tears 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 destroyed before being brought up again.