Media Manager Storage Unit Considerations

NetBackup keeps records about the files in the backups and about the media where the records are stored. Media Manager manages the removable storage units (for example, tape drives) and tracks the location of both online and offline volumes. If the storage unit is on disk, the data goes to the file path specified during configuration of the storage unit. The operating system disk manager manages the actual reading and writing of data.

When sending a backup to a Media Manager storage unit, NetBackup looks in its media catalog for a previously used volume that is the correct density and is configured to retain backups for the desired period of time. If none of the previously used volumes are suitable, NetBackup requests a new media ID from Media Manager and then requests Media Manager to mount the volume in a device.

The request to Media Manager specifies both the media ID and device density of the volume. If a request involves a robot, the volume is then automatically mounted in a drive and assigned to the request. With a standalone drive, NetBackup attempts to use the media that is in the drive.

If a standalone drive does not contain media or if the required volume is not available to a robot, Media Manager displays a mount request. An operator can then find the volume, mount it manually, and assign it to the drive.

To restore from a Media Manager storage unit, NetBackup finds the media ID in its media catalog and requests the volume from Media Manager.

The following rules apply when adding Media Manager storage units:

1. If using NetBackup Enterprise Server: Add the storage unit to the master server, specifying the media server where the drives attach.

   If using NetBackup Server: Add the storage unit to the server where the drives attach. The robotic control must also attach to that server.

2. The number of storage units that you must create for a robot depends on the robot's drive configuration as follows:
   • Drives with the same density on the same media server must be in the same storage unit. For example, if a robot has two drives of the same density on the same media server, add only a single storage unit for the robot. Set the Maximum Concurrent Drives Used for Backup setting to 2.
   • Drives with different densities must be in separate storage units. For example, an STK 9710 library configured in Media Manager as a Tape Library DLT (TLD) can have both half-inch cartridge and DLT drives. Here, you must define a separate storage unit for each density.

   Applies only to NetBackup Enterprise Server:

   • Drives on different media servers must be in separate storage units.

   Applies only to NetBackup Enterprise Server:

   If a robot's drives and robotic control attach to different NetBackup servers, specify the server where the drives attach as the media server. Always specify the same robot number for the drives as is used for the robotic control.

3. Standalone drives with the same density must be in the same storage unit.

   For example, if a server has two 1/4-inch qscsi drives, add a storage unit with Maximum Concurrent Drives Used for Backup set to 2. Media Manager chooses the drive to use when NetBackup sends a backup to this storage unit.

4. Standalone drives with different densities must be in different storage units.
5. A robot and a standalone drive cannot be in the same storage unit.