Reverting to the previous level of GPFS
If you should decide not to continue the migration to the latest level of GPFS™, and you have not yet issued the mmchfs -V command, you can reinstall the earlier level of GPFS.
Important: Once a file system has been migrated
explicitly by issuing the mmchfs -V full command,
the disk images can no longer be read by a prior version of GPFS. You will be required to re-create
the file system from the backup media and restore the content if you
choose to go back after this command has been issued. The same rules
apply for file systems that are newly created with GPFS 4.2.
You can revert back to GPFS 4.1.x.
If you have performed backups with the mmbackup command using the 4.2 version and decide to revert to an earlier version, you must rebuild the mmbackup shadow database using the mmbackup command with either the -q or --rebuild option.
The procedure differs depending on whether you have issued the mmchconfig release=LATEST command or not.