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AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
Backup and Restore GuideThe HCL OneDB™ Backup and Restore Guide describes how to use the HCL® OneDB® ON-Bar and ontape utilities to back up and restore database server data. These utilities enable you to recover your databases after data is lost or becomes corrupted due to hardware or software failure or accident.
Overview of backup and restoreThese topics provide an overview of backup and restore concepts. They also provide information about planning for backup and restore operations.
Backup and restore conceptsHCL OneDB™ provides two utilities for backing up and restoring database server data. Both utilities back up and restore storage spaces and logical logs. However, they support different features and it is important to know the differences. These topics explain basic backup and restore concepts for HCL® OneDB® database servers and compares the ON-Bar and ontape utilities.
Recovery systemA recovery system, which includes backup and restore systems, enables you to back up your database server data and later restore it if your current data becomes corrupted or inaccessible.
Restore systemsA restore recreates database server data from backed-up storage spaces and logical-log files.
Physical and logical restoresON-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 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.

This figure shows data moving from backup media to dbspaces. — Figure 1: Physical restore

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.

This figure is described in the surrounding text. — Figure 2: Logical restore

The database server automatically knows which logical logs to restore.

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