Accessing snapshots through NFS exports and SMB shares
NFS exports and SMB shares can easily access snapshots, so that users can restore older versions file systems.
- The root directory in any NFS export contains a
.snapshotdirectory which, in turn, contains directory trees for each of the snapshots. Each of these directory trees consists of a frozen image of the file systems that were accessible from the export at the time the snapshot was taken (access privileges for these files are preserved intact). - Similarly, the top-level folder in any SMB share contains a
~snapshotfolder with similar characteristics. Both with NFS and with SMB, each directory accessible from the export (share) also contains a hidden.snapshot (~snapshot)directory which, in turn, contains frozen images of that directory. A global setting can be used to hide.snapshotand~snapshotfrom NFS and SMB clients.NoteBacking up or copying all files at the root of an NFS export or an SMB share can have the undesired effect of backing up multiple copies of the directory tree (that is, current file contents plus images preserved by the snapshots; for example, a 10 GB directory tree with four snapshots would take up approximately 50 GB).Administrators can control access to snapshot images by disabling snapshot access for specific NFS exports and SMB shares. For example, by creating one set of shares for users with snapshots disabled, and a second set of shares with restricted privileges (for administrator access to snapshot images).