Physical and logical restores

ON-Bar and ontape restore database server data in two phases. The first phase is the physical restore, which restores data from backups of all or selected storage spaces. The second phase is the logical restore, which restores transactions from the logical-log backups.

Physical restore

During a physical restore, ON-Bar or ontape restores the data from the most recent level-0, level-1, and level-2 backups. When you suffer a disk failure, you can restore to a new disk only those storage spaces with chunks that resided on the failed disk. The following figure illustrates a physical restore.
Figure 1. Physical restore
This figure shows data moving from backup media to dbspaces.

Logical restore

As the following figure shows, the database server replays the logical logs to reapply any database transactions that occurred after the last backup. The logical restore applies only to the physically restored storage spaces.
Figure 2. Logical restore
This figure is described in the surrounding text.

The database server automatically knows which logical logs to restore.

For more information, see Restore data with ON-Bar and Restore with ontape.