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

Deleting nodes from your GPFS nodeset

You can delete nodes from an existing GPFS nodeset by issuing the mmdelnode command. You must follow these rules when deleting nodes:

1. Before you can delete a node, you must unmount all of the GPFS file systems and stop GPFS on the node to be deleted.
2. Exercise caution when deleting nodes from the GPFS nodeset. In a multi-node quorum environment, if the number of remaining nodes falls below the requirement for a quorum, you will be unable to perform file system operations (see the IBM General Parallel File System for AIX: Concepts, Planning, and Installation Guide and search for quorum).
3. If the number of nodes remaining in the nodeset falls below three, you must run the mmchconfig command if you want to change the quorum algorithm to single-node quorum.

   Note:

   In a two-node cluster, Fibre Channel disks are not supported in a single-node quorum environment.

4. When a node is deleted from a GPFS nodeset, its entry is not automatically deleted from the nodeset configuration. Instead, the node is only marked as deleted. This allows nodes to be deleted without having to stop GPFS on all nodes. Such deleted nodes are not a factor when calculating quorum. They are also available to the mmaddnode and mmconfig commands for inclusion into another GPFS nodeset. If you want to remove any deleted node entries from the nodeset configuration, you must use the -c option on the mmdelnode command. This can be done when the node is deleted, or anytime later (see the mmdelnode Command).

For example, to delete node k145n29, you would specify the hostname used during configuration:

mmdelnode -c k145n29

The -c option tells GPFS to remove the entry for k145n29, as well as any other left over entries for previously deleted nodes, from its configuration information.

The system displays information similar to:

Verifying GPFS is stopped on all nodes ...
mmdelnode: 6027-1370 Removing old nodeset information from the deleted nodes.
This is an asynchronous process.
mmdelnode: 6027-1371 Propagating the changes to all affected nodes.
This is an asynchronous process.
 

See the mmdelnode Command for complete usage information.