GPFS: Administration and Programming Reference - IRA Home

v Change the primary or secondary GPFS cluster configuration server nodes. The primary or secondary
server may be changed to another node in the GPFS cluster. That node must be available for the
command to be successful.
Attention: If during the change to a new primary or secondary GPFS cluster configuration server, one
or both of the old server nodes are down, it is imperative that you run the mmchcluster -p LATEST
command as soon as the old servers are brought back online. Failure to do so may lead to disruption in
GPFS operations.
v Synchronize the primary GPFS cluster configuration server node. If an invocation of the mmchcluster
command fails, you will be prompted to reissue the command and specify LATEST on the -p option to
synchronize all of the nodes in the GPFS cluster. Synchronization instructs all nodes in the GPFS
cluster to use the most recently specified primary GPFS cluster configuration server.
v Change the remote shell and remote file copy programs to be used by the nodes in the cluster. These
commands must adhere to the syntax forms of the rsh and rcp commands, but may implement an
alternate authentication mechanism.
For example, to change the primary server for the GPFS cluster data, enter:
mmchcluster -p k164n06
The system displays information similar to:
mmchcluster -p k164n06
mmchcluster: Command successfully completed
To confirm the change, enter:
mmlscluster
The system displays information similar to:
GPFS cluster information
========================
GPFS cluster name: cluster1.kgn.ibm.com
GPFS cluster id: 680681562214606028
GPFS UID domain: cluster1.kgn.ibm.com
Remote shell command: /usr/bin/rsh
Remote file copy command: /usr/bin/rcp
GPFS cluster configuration servers:
-----------------------------------
Primary server: k164sn06.kgn.ibm.com
Secondary server: k164n05.kgn.ibm.com
Node Daemon node name IP address Admin node name Designation
-------------------------------------------------------------------------------------
1 k164n04.kgn.ibm.com 198.117.68.68 k164n04.kgn.ibm.com quorum
2 k164n05.kgn.ibm.com 198.117.68.69 k164n05.kgn.ibm.com quorum
3 k164n06.kgn.ibm.com 198.117.68.70 k164sn06.kgn.ibm.com quorum-manager
Attention: The mmchcluster command, when issued with either the -p or -s option, is designed to
operate in an environment where the current primary and secondary GPFS cluster configuration servers
are not available. As a result, the command can run without obtaining its regular serialization locks. To
assure smooth transition to a new cluster configuration server, no other GPFS commands (mm...
commands) should be running when the command is issued nor should any other command be issued
until the mmchcluster command has successfully completed.
See the “mmchcluster Command” on page 84 and the “mmlscluster Command” on page 198 for complete
usage information.
Chapter 2. Managing your GPFS cluster 7