Using the Oracle-Suggested Backup Strategy

Using the Oracle-Suggested Backup Strategy

Enterprise Manager makes it easy to set up an Oracle-suggested backup strategy for backups to disk that protects your data and provides efficient recoverability to any point in the a recovery window of your choosing. (In the simplest case, examined in this section, this window is 24 hours.) The Oracle-suggested strategy leverages Oracle's incremental backup and incrementally-updated backup features to provide faster backups than whole database backups, and faster recoverability than is possible through applying database changes from the archived log to your datafiles.

The Oracle-suggested backup strategy is based on creating an image copy of your database. This copy is rolled forward by means of incrementally updated backups. Oracle Enterprise Manager schedules RMAN backups jobs for you to run during the overnight hours.

For each datafile, the strategy calls for backups as follows:

At the beginning of day 1 of the strategy (the time the first scheduled job actually runs), an incremental level 0 datafile copy backup. It contains the datafile's contents at the beginning of day 1.

In a restore-and-recovery scenario, the redo logs from day 1 can be used to recover to any point during day 1.

At the beginning of day 2, an incremental level 1 backup is created, containing the blocks changed during day 1.

In a restore-and-recovery scenario, this incremental level 1 can be applied to quickly roll forward the level 0 backup to the beginning of day 2, and redo logs can be used to recover to any point during day 2.

At the beginning of each day n for days 3 and onwards, the level 1 backup from the beginning of day n-1 is applied to the level 0 backup. This brings the datafile copy to its state at the beginning of day n-1. Then, a new level 1 is created, containing the blocks changed during day n-1.

In a restore-and-recovery scenario, this incremental level 1 can be applied to the datafile rolled forward on day n-1 to the beginning of day n, and redo logs can be used to recover the database to any point during day n.

The datafile copies used in the Oracle-suggested backup strategy are tagged with the tag ORA$OEM_LEVEL_0. The level 1 incremental backups for use in this strategy are created for use with datafile copies that are so labelled. You can safely implement other backup strategies without concern for interference from the backups for the Oracle suggested strategy.

There are also Oracle-suggested strategies that use tape backups along with disk backups, but those are beyond the scope of this chapter.

Backing Up Your Database With the Oracle-Suggested Disk Backup Strategy Follow these steps to use the Oracle-suggested strategy to back up to disk:

1. In the Backup/Recovery section of the Maintenance page, click Schedule Backup. The Schedule Backup page appears, as shown in Figure 9–1 .

Performing Backup and Recovery 9-15

2. In the Oracle-Suggested Backup section, click the Schedule Oracle-Suggested Backup button.

The Schedule Oracle-Suggested Backup:Destination page appears. On this page, you select the destination media for the backup, which can be disk, tape or both.

3. Select Disk as the destination and click Next. The Schedule Oracle-Suggested Backup: Setup page. This page describes the

backups that are performed each day as part of the disk-based strategy.

4. There are no settings to change on this page. Click Next The Schedule Oracle-Suggested Backup: Schedule page appears.

5. You are prompted for Start Date, Time Zone, and Daily Backup Time for the daily backups. Based upon your expected usage patterns, choose times for the nightly backup during which database activity is low. Click Next.

The Schedule Oracle-Suggested Backup: Review page appears.

6. The backup script RMAN will run is displayed (although you cannot edit the script directly). You are presented with a chance to confirm or alter your settings. In the backup script, you can see the tag ORA$OEM_LEVEL_0 that the script assigns to the backup. Assuming you do not need to change the schedule, click Submit Job to add the job for the Oracle-suggested strategy to your schedule.

Your database will now be backed up once daily, using incremental backups and incrementally applied backups, allowing quick recovery to any time in the preceding 24 hours.