Oracle Backup and Recovery (1 of 2)

  1. Backup and Recovery Considerations
    1. Define requirements for a backup and recovery strategy
      1. A thurough understanding of the business,operational, and technical requirements this will help develop an effective backup and recovery strategy that will protect the database from different types of failures and insure high availability, minmal downtime and complete data recovery.
      2. Regularly test the backup and recovery strategy, because it ensures integrity of backups, the validity of the backup and recovery methods,and the reduction of problems before they occur in a production database.
    2. Articulate the importance of management concurrence for the strategy
    3. It ensures that there will always be an on-line duplicate (hot backup) of the database and also helps avoid a CLI (Career Limiting Incident) !!.

    4. Identify the components of a disaster recovery plan
    5. A disaster recovery plan consists of preparing for unlikely events, but depending on what part of the world you are, this could be more than likely. Some of them might be:

      1. Natural Disasters(Floods,Hurricanes)
      2. Blackouts
      3. Hardware Failure
      4. Key Personnel departure
      5. Viruses
      6. Theft

      It is recommended that you make a Disaster Recovery Plan that contemplates the previously mentioned contigencies you might encounter. The recovery plan should at a minimum consider Data, Equipment, Personnel and Facilities . If you are knowledgeable in spanish: "Backups" might be of interest to you.

    6. List Oracle Server features in the context of high availablilty
    7. The Oracle backup and recovery functionality relies on many components of the Oracle server architecture, including memory strcuture, background processes, and the physical database structure. (The following objectives pretty much cover these features)

    1. List the strengths of different database configurations for recoverability.
    2. The two main configurations for running a database are ARCHIVELOG and NOARCHIVELOG. Assuming a recovery operation is needed the following scenarios could arise:

      If the database is in ARCHIVELOG there are two possibilities:

      1. Complete-Recovery : The database is restored and recovered through the applicaion of ALL redo information (this includes both the online and archived redo log files) since the last backup. This type of recovery is performed normally when one of more data files or control files are damaged, the damaged files are recovered using al the redo information generated since the last full backup.
      2. Incomplete-Recovery: In this scenario the database is restored and recovered through the application of only SOME of the redo information generated since the last backup. This type of recovery is normally used when an on-line redo log file is lost due to hardware failure or a certain user requires to backup to a certain point in time,in simpler terms, an incomplete recovery only rollsback certain transactions without the need to involve ALL the redo-log files.

      If the database is in NOARCHIVELOG:

      You benefit from not having to save all the on-line redo log files, on heavily accesed systems this type of configuration alleviates disk-space usage,because in ARCHIVELOG every on-line redo log file is eventually backed-up; these archived redo-log files can easily fill up a WHOLE disk (10-12 GB) in a matter of hours. However the disadvantage of running this configuration is that in the event of a failure your only means of backup is by your last backup tape, Oracle cannot help in this case because it does not have a history of previous redo-log files , the ones that are ARCHIVED in ARCHIVELOG mode.

    3. Discuss the importance of testing a backup and recovery plan
    4. Testing the backup and recovery plan ensures:

        1. That the backup and recovery methods are sound
        2. Integrity of backups
        3. Ensures that the backup and recovery strategy meets business needs.
        4. It minimizes problems before they occur in a production environment.
        5. It ensures that personnel can react quickly and effectively in case any errors arise,avoiding a crisis situation.