7 Replies Latest reply on Sep 3, 2013 7:49 AM by Selvakumar.Nagulan

    RMAN backup from SCN to SCN???


      OS: AIX 5.3



      Hi All,


      We have corruption on our standby database due to an incomplete archive log that was applied. To resolve this we are taking an incremental backup from Production using the FROM SCN keyword, The incremental will go back over one day, and due to the volume of data per day this will create a number of very large backup pieces (100+ GB) which will need to be transferred (gzipped) across the network.


      As you can see below this is the command we run:


      Perform an incremental backup on Production from the SCN number you are having issues with.

      ALLOCATE CHANNEL ch1 DEVICE TYPE DISK FORMAT '/omnorapb/u96/backup/%U';
      ALLOCATE CHANNEL ch2 DEVICE TYPE DISK FORMAT '/omnorapb/u96/backup/%U';
      backup incremental from scn 81850837401 database;
      release channel ch1;
      release channel ch2;


      I thought about a scenario where we only backup between a range of SCN's. For Example: from SCN 123456 TO SCN 123458 but can not find anything online specific to a backup. Is this possible? and if not is there a technical reason why not? We have already transferred the future archived logs (archived created after the corrupt log), so don't want to duplicate the data in the backup.


      Thanks in advance.

        • 1. Re: RMAN backup from SCN to SCN???




          You can check MOS Doc :Steps to perform for Rolling forward a standby database using RMAN Incremental Backup. (Doc ID 836986.1)




          • 2. Re: RMAN backup from SCN to SCN???



            If you have the archivelogs generated after the corrupt/incomplete archive log, you can restore only the archive log/logs that was needed for the recovery to resume apply.


            RMAN> restore archivelog sequence between 123 and 125; -- Here archive log sequence 124 is corrupt/missing



            Once restored from the backup, then you can transfer the log to standby site and restart the apply.



            Thank you!!

            • 3. Re: RMAN backup from SCN to SCN???

              Hi nagulan.selvakumar,


              Thanks for your response. We have no need to restore the archive logs as I have the archive log 74 on production (corrupted on standby only), and can ftp the file over. Issue is managed recover applied the corrupt file 74 and now is throwing errors ORA-10567: Redo is inconsistent with data block when trying to apply the next archive log 75. Archive log 74 was only a partial file which oracle applied.


              SQL> alter database recover managed standby database;
              alter database recover managed standby database
              ERROR at line 1:
              ORA-00600: internal error code, arguments: [3020], [1709], [975869],[2878268413], [], [], [], [], [], [], [], []
              ORA-10567: Redo is inconsistent with data block (file# 1709, block# 975869,file offset is 3699351552 bytes)
              ORA-10564: tablespace OMNI_AUTH_LD_2013_AUG_ENC
              ORA-01110: data file 1709:'/om2orapb/u05/oradata/BW3/BW3_omni_auth_ld_2013_aug_enc_01.dbf'
              ORA-10560: block type '0'


              I need to restore/recover the database back to archive log 73 (the last archive applied before the partial/corrupt file 74).


              To resolve this before we took an incremental backup using the FROM SCN keyword. I'm just trying to reduce the size of the backup we take to fix the corrupt archive log that was applied. If this can be fixed using an alternative approach then its worth considering.



              • 4. Re: RMAN backup from SCN to SCN???

                Your Standby database has already gone forward.  How will you apply the incremental backup taken from lower SCN to a stdby database which is already past that SCN.

                This will be possible if u have previous full backup of standby database taken before the incremental backup scn.  Otherwise u may have to re-build the standby database.

                • 5. Re: RMAN backup from SCN to SCN???

                  I think he is talking about taking a backup from production database and bringing it across to the standby, then recovering on standby using the incremental, but he does not want the backup to be too big so wants to know can you backup between two SCN numbers, I would presume he would allow standby to kick back in and apply any left over archive logs after that. Have a look at 836986.1 on oracle support.

                  Nosnikrap, I've had a look online to see if you can do a backup from between a range of SCN numbers, but i don't think this is possible. Lets hope for your sake im wrong. It would be interesting to know as we had a similar issue recently.

                  • 6. Re: RMAN backup from SCN to SCN???
                    Hemant K Chitale

                    >I thought about a scenario where we only backup between a range of SCN's


                    You cannot specify a FROM .. TO range.


                    The BACKUP FROM SCN command is specifically for incremental backups to be restored to a standby.



                    Hemant K Chitale

                    • 7. Re: RMAN backup from SCN to SCN???



                      From the error report posted, I'm afraid that your standby is suffering with "Stuck recovery".

                      The ORA-600 [3020] stuck recovery error could occur on the Standby database for several reasons including: a lost write on the Primary, a lost write on the Standby, missing redo, or logical corruption on the primary resulting in an incomplete redo chain.

                      For complete cause and solution, please take a look at below to resolve the issue.

                      Resolving ORA-752 or ORA-600 [3020] During Standby Recovery (Doc ID 1265884.1)

                      Thank you!!