IBM General Parallel File System for AIX: Administration and Programming Reference

Changing node names and IP addresses

GPFS assumes that IP addresses, node names, and reliable hostnames remain constant. In the rare event that such a change becomes necessary, follow these steps:

1. Before any of the names or IP addresses are changed:
   • In an SP environment, use the SDRRetrieveFile command to create a backup copy of the GPFS configuration and file system information in the /var/mmfs/gen/mmsdrfs2 file.
   • In an HACMP environment, on the primary GPFS cluster data server, backup the /var/mmfs/gen/mmsdrfs file.
   • Create a file containing the names of all the nodes in your GPFS nodeset by either:
     • Copying the /etc/cluster.nodes file.
     • Issuing the mmlsnode command and archive the information.
   • Use the mmshutdown command to stop GPFS on all affected nodes.
   • Use the mmdelnode command to delete the affected nodes from their respective GPFS nodeset.

     If all nodes in the nodeset are affected, issue the mmdelnode -P -a to preserve the configuration information after the last node has been deleted from the nodeset.

   • In an HACMP environment, use the mmdelcluster command to delete all affected nodes from the GPFS cluster.
2. Change the node names and IP addresses. In an SP environment, see the IBM Parallel System Support Programs for AIX: Administration Guide and search for changing the IP address and hostnames. In an HACMP environment, see the High Availability Cluster Multi-Processing for AIX: Enhanced Scalability Installation and Administration Guide, Volume 2 and search for changing the cluster configuration.
3. In an SP environment, use the mmaddnode command to add the nodes back into their nodeset.
4. In an HACMP environment, issue the mmaddcluster command to add the nodes back to the GPFS cluster before using the mmaddnode command to add the nodes back into their nodeset.