Duplicating Backup Images

NetBackup can create up to 10 copies of unexpired backups. Indicate the number of backup copies in Host Properties > Master Servers > Global Attributes > Maximum backup copies.

NetBackup can create up to four of the copies simultaneously.

An alternative to taking time to duplicate backups is to use Inline Tape Copy. Inline Tape Copy allows you to create up to four copies simultaneously at backup time. Keep in mind that an additional drive is required for each copy and the destination storage units cannot be optical disk, NDMP, QIC, or third-party copies. The backup time may be longer than for one copy only.

NetBackup does not verify in advance whether the storage units and drives required for the duplicate operation are available for use, only that the destination storage unit exists. The storage units must be connected to the same media server.

The following lists describe scenarios which present candidates for duplication and scenarios where duplication is not possible:

Notes on Multiplexed Duplication

• When duplicating multiplexed SQL-BackTrack backups with multiplex mode enabled, it is necessary to duplicate all the backups in the multiplexed group. This ensures that the fragment order and size is maintained in the duplicate. Otherwise, it is possible that restores from the duplicated backups will not work. A multiplexed group is a set of backups that were multiplexed together during a single multiplexing session.
• When duplicating multiplexed backups, the multiplex settings of the destination storage unit and the original schedule are ignored. However, if multiple multiplexed groups are duplicated, the grouping within each multiplexed group is maintained. This means that the duplicated groups will have a multiplexing factor that is no greater than that used during the original backup.
• If all backups in a multiplexed group are duplicated to a storage unit that has the same characteristics as the one where the backup was originally performed, the duplicated group will be identical, with the following exceptions:
• If EOM (end of media) is encountered on either the source or destination media.
• If any of the fragments in the source backups are zero length (occurs if many multiplexed backups start at the same time), then during duplication these zero length fragments are removed. (This concerns only for SQL-BackTrack backups.)

  To duplicate backup images

1. In the NetBackup Administration Console, expand NetBackup Management > Catalog.
2. Set up the search criteria for the image you wish to duplicate. Click Search Now.
3. Right-click the image you wish to duplicate and select Duplicate from the shortcut menu. The Setup Duplication Variables dialog appears.
4. Specify the number of copies you would like created.

   If there are enough drives available, the copies will be created simultaneously. Otherwise, the system may require operator intervention if, for instance, four copies are to be created and there are only two drives.

5. The primary copy is the copy from which restores will be done. Normally, the original backup will be the primary copy.

   If you want one of the duplicated copies to become the primary copy, check the appropriate check box, otherwise leave the fields blank.

   When the primary expires, a different copy automatically becomes primary. (The one chosen is the one with the smallest copy number. If the primary is copy 1, when it expires, copy 2 becomes primary. If the primary is copy 5, when it expires, copy 1 becomes primary.)

6. Specify the storage unit where each copy will be stored. If a storage unit has multiple drives, it can be used for both the source and destination.

   ---

     Note    Inline Tape Copy does not support the following storage types: NDMP, third-party copies, or optical devices.
   Also, Inline Tape Copy does not support storage units that use a QIC (quarter-inch cartridge) drive type.

   ---

7. Specify the volume pool where each copy will be stored.

   NetBackup does not verify in advance that the media ID selected for the duplicate copy is not the same as the media ID of the volume that contains the original backup. Because of this potential deadlock, specify a different volume pool to ensure a different volume is used.

8. Select the retention level for the copy, or select No change.

   The duplicate copy shares many attributes of the primary copy, including backup ID. Other attributes, such as elapsed time, apply only to the primary. It is the primary copy that NetBackup uses to satisfy restore requests.

   • If No Change is selected for the retention period, the expiration date is the same for the duplicate and source copies. You can use the bpexpdate command to change the expiration date of the duplicate.
   • If a retention period is indicated, the expiration date for the copy is the backup date plus the retention period. For example, if a backup was created on November 14, 2002 and its retention period is one week, the new copy's expiration date is November 21, 2002.
9. Specify whether the remaining copies should continue or fail if the specified copy fails.
10. If the selection includes multiplexed backups and the backups are to remain multiplexed in the duplicate, check Preserve Multiplexing. If you do not duplicate all the backups in a multiplexed group, the duplicate will have a different layout of fragments. (A multiplexed group is a set of backups that were multiplexed together during a single session.)

    By default, duplication is done serially and attempts to minimize media mounts and positioning time. Only one backup is processed at a time. If Preserved Multiplexing is enabled, NetBackup first duplicates all backups that cannot be multiplex duplicated before the multiplexed backups are duplicated.

    Preserve Multiplexing does not apply when the destination is a disk storage unit or disk staging storage unit. However, if the source is a multiplexed tape and the destination is a disk storage unit or disk staging storage unit, selecting Preserve Multiplexing ensures that the tape is read in only one pass rather than multiple passes.

11. Click OK to start duplicating.
12. Click the Results tab, then select the duplication job just created to view the job results. See Viewing Job Results.