Filesets and backup

The mmbackup command and IBM Spectrum Protect™ are unaware of the existence of filesets. When restoring a file system that had been backed up to IBM Spectrum Protect, the files are restored to their original path names, regardless of the filesets of which they were originally a part.

IBM Spectrum Protect has no mechanism to create or link filesets during restore. Therefore, if a file system is migrated to IBM Spectrum Protect and then filesets are unlinked or deleted, restore or recall of the file system does not restore the filesets.

During a full restore from backup, all fileset information is lost and all files are restored into the root fileset. It is recommended that you save the output of the mmlsfileset command to aid in the reconstruction of fileset names and junction locations. Saving mmlsfileset -L also allows reconstruction of fileset comments. Both command outputs are needed to fully restore the fileset configuration.

A partial restore can also lead to confusion if filesets have been deleted, unlinked, or their junctions moved, since the backup was made. For example, if the backed up data was in a fileset that has since been unlinked, the restore process puts it into files and directories in the parent fileset. The unlinked fileset cannot be re-linked into the same location until the restored data is moved out of the way. Similarly, if the fileset was deleted, restoring its contents does not recreate the deleted fileset, but the contents are instead restored into the parent fileset.

Since the mmbackup command operates by traversing the directory structure, it does not include the contents of unlinked filesets, even though they are part of the file system. If it is desired to include these filesets in the backup, they should be re-linked, perhaps into a temporary location. Conversely, temporarily unlinking a fileset is a convenient mechanism to exclude it from a backup.

In summary, fileset information should be saved by periodically recording mmlsfileset output somewhere in the file system, where it is preserved as part of the backup process. During restore, care should be exercised when changes in the fileset structure have occurred since the backup was created.