Backup and restore operations by using the NetApp SnapMirror to Tape feature

You can back up large NetApp file systems by using the NetApp SnapMirror to Tape feature (also known as SMTape). Using a block-level copy of data for backup, the SnapMirror to Tape method is faster than a traditional NDMP full backup and can be used when NDMP full backups are impractical.

Use the NDMP SnapMirror to Tape feature as a disaster recovery option for copying large NetApp file systems to auxiliary storage. For most NetApp file systems, use the standard NDMP full or differential backup method.

By specifying a parameter on the BACKUP NODE and RESTORE NODE commands, you can back up and restore file systems by using SnapMirror to Tape. There are several limitations and restrictions on how SnapMirror images can be used. Consider the following guidelines before you use it as a backup method:

• If you installed NetApp ONTAP 8.2 or later, you must define a data mover of type NASCLUSTER or NASVSERVER for SnapMirror to Tape operations.
• You cannot initiate a SnapMirror to Tape backup or restore operation from the Tivoli® Storage Manager Operations Center, web client, or command-line client.
• You cannot perform differential backups of SnapMirror images.
• You cannot perform a directory-level backup by using SnapMirror to Tape. Therefore, Tivoli Storage Manager does not permit SnapMirror to Tape backup operations on a server virtual file space.
• You cannot perform an NDMP file-level restore operation from SnapMirror to Tape images. Therefore, a table of contents is never created during SnapMirror to Tape image backups.
• At the start of a SnapMirror to Tape copy operation, the file server generates a snapshot of the file system. NetApp provides an NDMP environment variable to control whether this snapshot is removed at the end of the SnapMirror to Tape operation. Tivoli Storage Manager always sets this variable to remove the snapshot.
• After a SnapMirror to Tape image is retrieved and copied to a NetApp file system, the target file system remains configured as a SnapMirror partner. NetApp provides an NDMP environment variable to control whether this SnapMirror relationship should be broken. Tivoli Storage Manager always "breaks" the SnapMirror relationship during the retrieval. After the restore operation is complete, the target file system is in the same state as that of the original file system at the time of backup.

For more information about the SnapMirror to Tape feature, see BACKUP NODE (Back up a NAS node) and RESTORE NODE (Restore a NAS node).