[root@nsd1]# mmdelnode -N node-c01 Verifying GPFS is stopped on all affected nodes ... node-c01-nas: mmremote: Unknown GPFS execution environment mmdelnode: Command failed. Examine previous error messages to determine cause.
If you do a mmgetstate -a on the NSD node, you will get something like this
# mmgetstate -a ..... ..... 05 node-c01 unknown ..... .....
The resolution is not too difficult. According to IBM GPFS Administration and Programming References mmdelnode
You have to power down the affected node and do the mmdelnode again. You can see it is successful.
# mmdelnode -N node-c01 Verifying GPFS is stopped on all affected nodes ... mmdelnode: Command successfully completed mmdelnode: Propagating the cluster configuration data to all affected nodes. This is an asynchronous process.
Do a mmgetstate -a and you will see that the node deletion is successful