White Papers

Best Practices for Oracle 11g Backup and Recovery using RMAN and Dell EqualLogic Snapshots

6 Test design and results: point-in-time recovery using

Oracle FLASHBACK DATABASE vs. EqualLogic

snapshots

There are many scenarios where database administrators chose to recover databases to specific points

in time. For example, if an error occurred (such as inadvertent table deletion or database corruption),

the first thing a DBA does is recover the database to a time prior to when the database corruption

occurred.

Traditional point-in-time recovery involves restoring the database files to the previous time and then

applying the redo logs until you reach a point in time just before corruption occurred. This process

can take a long time, depending on when the previous backup was performed and the number and

size of the redo logs that need to be applied.

Oracle’s FLASHBACK DATABASE is a feature that helps to accelerate the point in time recovery

process. This feature provides a better alternative than standard point-in-time or incomplete recovery

methods.

We also evaluated point-in-time recovery using EqualLogic based snapshots. The results presented in

Section 6.3 show that you can significantly shorten the time required to complete point-in-time

recovery (relative to Oracle FLASHBACK DATABASE) by using EqualLogic based snapshots.

6.1 Point-in-time recovery using Oracle FLASHBACK DATABASE

The high-level steps followed to configure Oracle FLASHBACK DATABASE feature are described

below.

Configuration prerequisites:

• The database must be running in archivelog mode.

• A flash recovery area must be configured for the database.

• The database must have been put in FLASHBACK mode

• The flashback retention target parameter must be set. This parameter determines how far back

the database can be rolled backwards.

High-level procedure for point-in-time recovery using Oracle FLASHBACK DATABASE (this process

assumes that the flashback database feature is not enabled yet):

1. Perform a clean shutdown of the database. This is a mandatory requirement for enabling the

FLASHBACK DATABASE feature.

2. Mount the database.

3. Enable FLASHBACK DATABASE feature

4. To recover the database to a point-in-time, shut down the database.