How the Browse Policy Works

You can recover a file that has an entry in the client file index through the Backup recover program, which enables users to browse and mark files and initiate data recovery. Client file index entries are not necessarily deleted the same day that the browse policy is exceeded. Backup does not remove the entry for a file until all the save sets that are dependent on the file have also exceeded their browse policies. In general, the entries for a full backup that are older than the browse policy are not removed until an additional length of time equal to one backup cycle passes as well. This extra time ensures that you can reconstruct a file to any point in time included in the browse policy period.

The following figures demonstrate how a browse policy affects data availability in the client file index. For more information about schedules, see "Schedule Configuration ", and for more information about backup levels, see "Backup Levels ".

In Figure 5-1, both the backup cycle and the browse policy are set at one week. A backup cycle is the length of time between full backups. Entries for the first full backup on October 2 remain in the client file index until all the incremental and level 5 backups that depend on it exceed the one-week browse policy. The full backup performed on October 2 is not removed until October 16, when the incrementals and level 5 that depend on the full backup expire.

Figure 5-1 One-Week Browse Policy

To illustrate why the browse policy works this way, suppose that on October 12, you decide that you want to recover information backed up on October 6. The backup performed on the 5th is an incremental backup dependent on the October 5 backup, which is a level 5 backup. The October 5 level 5 backup, in turn, is dependent on the full backup performed on October 2. The entry for the full backup performed on October 2 must remain in the client file index for a period of time equal to the browse policy (one week) plus one complete backup cycle (one additional week)--that is, until the level 5 backup on October 5 and all incremental backups dependent on the full backup pass their browse policy. In the example shown in Figure 5-1, entries from the Week 1 backup cycle are removed from the client file index on October 16.

In Figure 5-2, the browse policy is two weeks, which is twice as long as the backup cycle (1 week). In this example, on October 19 a user can still find browsable entries in the client file index from backups created on October 5. The backup performed on October 6 is an incremental backup dependent on the October 5 backup, which is a level 5 backup. The October 5 level 5 backup, in turn, is dependent on the full backup performed on October 2. The full backup performed on October 2, and the incremental and level backups that depend on it, must remain in the client file index for a period of time equal to the browse policy (two weeks), plus one complete backup cycle (one additional week). In this example, entries for the Week 1 backup cycle are not removed from the client index until October 23.

Figure 5-2 Two-Week Browse Policy