Choosing a Backup Strategy

You must decide how you plan to protect your database against potential failures. Before developing your backup strategy, answer the following questions.

Is it acceptable to lose any data if software or a disk failure damages some of the database files?

If it is not acceptable to lose any data, the database must be operated with archival recovery enabled, ideally with mirrored transaction journal volumes. Disk mirroring writes all information that is written to a primary disk to a secondary disk so that no data is lost if a disk failure occurs. For details about disk mirroring, see your operating system documentation.

If it is acceptable to lose a limited amount of data if there is a disk failure, you can operate the database with archival recovery disabled and avoid the work required to backup archive transaction journal files.
Will you ever need to recover to arbitrary times in the past?

If you need to recover to a specific date and time in the past to correct an erroneous operational or programmatic change to the database, ensure that you run with archival recovery enabled.
Does the database need to be available at all times (twenty-four hours a day, seven days a week)?

Do not operate the database without archival recovery enabled if the database must be available at all times, because the required whole database backups, taken while the database is shut down, cannot be made frequently, if at all. High-availability databases therefore always operate with archival recovery enabled and utilize online (or hot) backup capabilities.

An online backup can be performed on a database that has archival recovery disabled. However, the usefulness of the backup is diminished, as it is not possible to recover any transactions completed since the backup was made following a restore from backup.

As backing up and restoring a large database is a lengthy process, and backups of very large databases become impractical to perform on a regular basis for systems with high availability requirements, the Synchronized Database Service (SDS) provides an alternative recovery strategy. For details, see "Administering a JADE Synchronized Database Service (SDS) Environment", in Chapter 1 of the JADE Synchronized Database Service (SDS) Administration Guide.