Oracle Database 11g: High Availability Student Guide

A “data failure” is a missing, corrupted, or inconsistent data, log, control, or other file, whose content the Oracle instance cannot access. When your database has a problem, analyzing the underlying cause and choosing the correct solution is often the biggest component of down time. Oracle Database 11g offers several new and enhanced tools for analyzing and repairing database
problems.
• Data Guard, by allowing you to fail over to a standby database (that has its own copy of the data), enables you to continue operation if the primary database gets a data failure. Then, after failing over to the standby, you can take the time to repair the failed database (old primary)
without worrying about the impact on your applications. There are many enhancements to Data Guard.
• Data Recovery Advisor is a built-in tool that automatically diagnoses data failures and reports the appropriate repair option. If, for example, the Data Recovery Advisor discovers many bad blocks, it recommends restoring the entire file, rather than repairing individual blocks. Therefore, it assists you to perform the correct repair for a failure. You can either repair a data failure manually or request the Data Recovery Advisor to execute the repair for you. This decreases the amount of time to recover from a failure.