Tape media guidelines
If your environment contains virtual machine backup data on tape media (such as a tape storage pool or virtual tape library), and the data was either directly stored on tape or migrated to tape over time, consider these guidelines.
Configuration
- Ensure that virtual machine control file data is always on a disk storage pool. You can specify the destination storage pool for virtual machine control file data with the backup-archive client vmctlmc option. For more information, see Vmctlmc.
- Use collocation by file space to optimize the tape that contains virtual machine backup
data.
When a virtual machine is backed up to the Tivoli® Storage Manager server, each backup is represented as a separate file space on the server. The collocation by file space setting saves data from multiple incremental backups of the same virtual machine to the same volume (disk file). When migration to tape occurs, these backups are together on the physical tape.
You can enable collocation at the file space level with the Tivoli Storage Manager server COLLOCATE=FILESPACE parameter. For more information, see DEFINE STGPOOL
- Be aware of migration thresholds and how data availability is affected by thresholds. For example, a block in Data Protection for VMware that never changes can be migrated to tape even though the most active backup needs the block.
Recovery
You can restore files from tape media with either the Tivoli Storage Manager file restore interface or the Data Protection for VMware vSphere GUI Mount wizard. However, file restore reads data in a way that causes random read requests. As a result, processing might be slow when a sequential-access device (such as tape media) is used. File restore from disk storage is the preferred method.
Consider moving target virtual machine backup data from tape media to disk storage before you attempt a file restore operation. Do not move the virtual machine control data because this data should already be in separate disk storage pool. Also, do not move backup data to the disk storage pool on which the control data resides. If you move backup and control data to the same pool, you will have to complete an IFFULL backup to move the backup and control data to separate pools.
To move backup data, use the Tivoli Storage Manager server MOVE NODEDATA command and ensure that the FROMstgpool and TOstgpool parameters do not specify pools that contain control data.
Long term retention
Run traditional full VM backups to tape storage regularly as a solution for long-term storage or tape retention of your data. For example, you can run a full VM backup to tape monthly as a solution for archive needs.