12.5 Conclusion

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12.5 Conclusion

In this chapter we looked at some of the critical administrative functions that database administrators perform in their day-to-day work schedule. Backing up a database protects against potential loss or corruption of the data due to various reasons that may or may not be within human control. To provide this solution, we looked at the various types of backup options in Oracle and focused on RMAN. RMAN provides a comprehensive solution leading towards a 24 hours a day, 7 days a week operation, where no downtime is required for backing up the data. RMAN provides this functionality through the various backup strategies such as full, cumulative, and incremental backups. Incremental backups allow the opportunity for frequent backups, because Oracle only backs up data blocks that have changed since the previous backup.

We discussed the fact that while developing a compressive backup and recovery strategy is important, it is equally important to schedule testing of the backup and recovery strategy to ensure that the changes in business conditions and economic conditions have not invalidated this strategy.

Backups are taken to help recover the database from failures. Under this subject we discussed the various kinds of failures in a stand-alone Oracle configuration and the additional kinds of failures in a RAC configuration, for example the GCS failures. During these failure scenarios we also discussed how the data is recovered under these circumstances.

Recovery is not always done from backups and not always done by Oracle. There are certain features available in Oracle where a database administrator could perform operations by going back into the past and retrieving database activities. Tools such as flashback queries and LogMiner provide this opportunity.

In Chapter 15, we will start discussions on performance tuning of a RAC configuration. However, before we dive into this subject, let us discuss the various tools that would help make the performance tuning activity easy. The next chapter will discuss the tools and utilities used in performance tuning.