5 Replies Latest reply: May 22, 2012 10:08 PM by BHenriquez RSS

    Gaps on dataguard


      I want to know how can determine gaps on dataguard and cause of this gaps.

      Thanks for help :)
        • 1. Re: Gaps on dataguard
          you can find the archive log gap using v$archive_gap. gap between low sequence and high sequence. this gap will happen because of space issue,network issue etc.. if one archive log file is not applied from prod..that file is deleted in prod itself..remaining archive logs available in standby ... it won't apply in standby db... that gap u can find it using that view.. for that u can reconfigure again otherwise find scn from standby. based on that scn take incremental backup from prod.. and controlfile..and apply on standby and start with new controlfile...standby will sync without prod downtime..
          • 2. Re: Gaps on dataguard
            In addition you can use the dynamic performance views here:
            under Data Guard.
            • 3. Re: Gaps on dataguard
              What I do is use this summary query :


              Change DEST_ID=2 as needed.

              Both alert logs are a great source of the causes.

              -- Network outage
              -- Archive issue on Primary
              -- Transport issues
              -- Disk problem on primary

              Best Regards

              • 4. Re: Gaps on dataguard

                GAP's can occurred with many reasons

                1) archive log corruption
                2) unable to transfer as size is big and network speed is low
                3) any configuration of dataguard issue
                4) archives are deleted from OS level, or forcefully deleted?
                5) or the standby is behind from many days.

                If gap is more then perform incremental rollforward , check this link http://www.oracle-ckpt.com/rman-incremental-backups-to-roll-forward-a-physical-standby-database-2/
                • 5. Re: Gaps on dataguard
                  Thanks for you help :D