Fileset-level snapshots

Instead of creating a global snapshot of an entire file system, a fileset snapshot can be created to preserve the contents of a single independent fileset plus all dependent filesets that share the same inode space.

If an independent fileset has dependent filesets that share its inode space, then a snapshot of the independent fileset will also include those dependent filesets. In other words, a fileset snapshot is a snapshot of the whole inode space.

Each independent fileset has its own hidden .snapshots directory in the root directory of the fileset that contains any fileset snapshots. The mmsnapdir command allows setting an option that makes global snapshots also available through .snapshots in the root directory of all independent filesets. The .snapshots directory in the file system root directory lists both global snapshots and fileset snapshots of the root fileset (the root fileset is an independent fileset). This behavior can be customized with the mmsnapdir command.

Fileset snapshot names need not be unique across different filesets, so it is valid to use the same name for fileset snapshots of two different filesets because they will appear under .snapshots in two different fileset root directories.

You can restore independent fileset snapshot data and attribute files with the mmrestorefs command. For complete usage information, see mmrestorefs command.