If you have messed things up in the configuration and wish to redo the entire setup again, you have to do the following. From our training at GPFS, there are 2 advisable ways. The first one is the recommended way. The latter one is the “nuclear” option

Step 1: Unmount the GPFS file system

# mmumount /gpfs1 -a

Step 2: Delete GPFS file system. Deleting the file system and descriptors are important so that will not create issues during the subsequent file creation attempt

# mmdelfs /gpfs1

Step 3: Delete GPFS NSDs. Deleting the NSDs are important so that they will not create issues during the subsequent NSD creation.

# mmdelnsd nsd1-nas
# mmdelnsd nsd2-nas

Step 4: Shutdown GPFS daemons

# mmshutdown -a

Step 5: Delete the GPFS cluster

# mmdelnode -a

The “nuclear” option

Step 1: Unmount the GPFS file system
(Caution: GPFS cluster will be  erased and data will be lost)

# mmunmount /gpfs1 -a
# mmfsadm cleanup

Step 2: Delete selected configuration files on all nodes

# rm -f /var/mmfs/etc/mmfs.cfg
# rm -f /var/mmfs/gen/*
# rm -f /var/mmfs/tmp/*