Reduce fragment size setting

The Reduce fragment size setting specifies the largest fragment size that NetBackup can create to store backups.

For Media Manager storage units as follows:

The default maximum fragment size for a Media Manager storage unit is 1000 GB. To specify a maximum fragment size other than the default, place a check in the Reduce fragment size check box. Then enter a value from 50 megabytes to 1,048,575 megabytes.

Fragmenting multiplexed tape backups can expedite restores. Fragments allow NetBackup to skip to the specific fragment before searching for a file. Generally, NetBackup starts at the beginning of the multiplexed backup and reads tar headers until it finds the file.
For disk storage units

The default maximum fragment size for a disk storage unit is 524,288 megabytes. To specify a maximum fragment size other than the default, enter a value from 20 megabytes to 524,288 megabytes.

For media server deduplication pools and PureDisk deduplication pools, you can enter a value from 20 megabytes to 51200 megabytes.

Backups to disk are usually fragmented to ensure that the backup does not exceed the maximum size that the file system allows.

The Reduce fragment size setting is intended primarily for storing large backup images on a disk type storage unit.

Note:

OpenStorage vendors may have special requirements for the maximum fragment size. Consult the vendor's documentation for guidance.

If an error occurs in a backup, the entire backup is discarded. The backup restarts from the beginning, not from the fragment where the error occurred. (An exception is for backups where checkpoint restart is enabled. In that case, fragments before and including the last checkpoint are retained; the fragments after the last checkpoint are discarded.)

Note:

Basic disk staging units with different maximum fragment sizes may already be configured on a media server from a previous release. Upon upgrade, the disk storage units are not automatically increased to the new default of 524,288 megabytes. To make the best use of upgraded storage units, increase the fragment size on the upgraded storage units.