4 Replies Latest reply: Oct 28, 2013 8:22 PM by Hemant K Chitale RSS

    Purpose of Retention Policy Recovery Window and Redundancy

    K.Vijay

      Hi,

       

      Good Evening,

       

      I have some queries regarding the RMAN Retention Policy Recovery Window and Redundancy.

       

      1. Any condition is there to set the Retention Policy Recovery Window and Redundancy and control_file_record_keep_time?What is the relationship between these 3 parameters?

      2. Explain the scenario if i set the control_file_record_keep_time=4 Redundancy=3 and Recovery Window=7?

      3. If i set the Redundancy=3 and Recovery Window=7 means my backup place only have 3 copies of backup based on the redundancy then what is the purpose of Recovery Window=7 please give some example.

      4. If i change the values for Recovery Window=3 and Redundancy=7 what will happened, how many days backup will be available in my FRA location?Explain with one scenario?

       

      Thanks in advance.

      Vijay.

        • 2. Re: Purpose of Retention Policy Recovery Window and Redundancy
          K.Vijay

          DK,

           

          Thanks for your reply.

           

          I already read that document and got some idea about the RMAN Retention Policy Recovery Window and Redundancy.But i need more clarification regarding the Retention Policy Recovery Window and Redundancy and control_file_record_keep_time.

           

          Also i need practical answers for my mentioned scenarios.

           

          Thanks.

          • 3. Re: Purpose of Retention Policy Recovery Window and Redundancy
            DK2010

            Hi,

             

            Take a look of the above doc contents:

             

            Configuring the Backup Retention Policy

            As explained in "Backup Retention Policies", the backup retention policy specifies which backups must be retained to meet your data recovery requirements. This policy can be based on a recovery window or redundancy. Use the CONFIGURE RETENTION POLICY command to specify the retention policy.

            so  you have option to choose either  recovery windows or redundancy based you can set the configuration like

            read in the Doc What it said for both:

            Recovery Window-Based Retention Policy ==>RMAN does not consider any full or level 0 incremental backup as obsolete if it falls within the recovery window.  Additionally, RMAN retains all archived logs and level 1 incremental backups that are needed to recover to a random point within the window.

            Redundancy-Based Retention Policy==>The REDUNDANCY parameter of the CONFIGURE RETENTION POLICY command specifies how many full or level 0 backups of each datafile and control file that RMAN should keep. If the number of full or level 0 backups for a specific datafile or control file exceeds the REDUNDANCY setting, then RMAN considers the extra backups as obsolete. The default retention policy is REDUNDANCY 1.

             

            RMAN> show RETENTION POLICY;

             

             

            using target database control file instead of recovery catalog

            RMAN configuration parameters for database with db_unique_name DDTEST are:

            CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;

             

             

            RMAN> CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

             

             

            old RMAN configuration parameters:

            CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;

            new RMAN configuration parameters:

            CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

            new RMAN configuration parameters are successfully stored

             

             

            RMAN> show RETENTION POLICY;

             

             

            RMAN configuration parameters for database with db_unique_name DDTEST are:

            CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

             

             

            RMAN> CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;

             

             

            old RMAN configuration parameters:

            CONFIGURE RETENTION POLICY TO REDUNDANCY 3;

            new RMAN configuration parameters:

            CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;

            new RMAN configuration parameters are successfully stored

             

             

            RMAN> show RETENTION POLICY;

             

             

            RMAN configuration parameters for database with db_unique_name DDTEST are:

            CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;

             

            CONTROL_FILE_RECORD_KEEP_TIME:This parameter applies only to records in the control file that are circularly reusable (such as archive log records and various backup records) ref Doc:CONTROL_FILE_RECORD_KEEP_TIME


             

            1. Any condition is there to set the Retention Policy Recovery Window and Redundancy and control_file_record_keep_time?What is the relationship between these 3 parameters?

            2. Explain the scenario if i set the control_file_record_keep_time=4 Redundancy=3 and Recovery Window=7?

            3. If i set the Redundancy=3 and Recovery Window=7 means my backup place only have 3 copies of backup based on the redundancy then what is the purpose of Recovery Window=7 please give some example.

            4. If i change the values for Recovery Window=3 and Redundancy=7 what will happened, how many days backup will be available in my FRA location?Explain with one scenario?

             

            so i believe you can get the Answer from Your Question from Above details.

             

            HTH

            • 4. Re: Purpose of Retention Policy Recovery Window and Redundancy
              Hemant K Chitale

              I hope that you've understood by now (after *re-reading the documentation* !) that you cannot specify both Redundancy=3 and Recovery Window=7(days).  It is either REDUNDANCY   or    RECOVERY WINDOW.

               

               

              Hemant K Chitale