CephFS also supports snapshots down to a per-directory level; the snapshot doesn't need to include the whole CephFS filesystem. Each directory on a CephFS filesystem contains a hidden .snap directory; when a new sub directory is created inside, a snapshot is effectively taken and the view inside this new sub directory will represent the state of the original directory at the point when the snapshot was taken.
Multiple snapshots can be taken and browsed independently from each other, enabling the snapshots to be used as part of a short-term archiving scheme. One such use when CephFS is exported via Samba is to use the snapshot functionality to be exposed through the Windows Explorer previous versions tab.
In the following example, a test file is created, a snapshot taken, and then the file is modified. By examining the contents of the live and the file in the snapshot, we can see how CephFS snapshots present themselves:
