Data Guard out of sync...

 

Data Guard Issue - very high level view in Oracle Cloud Infrastructure (OCI)

Oracle Database Server build.

Recent issue following a network issue in OCI where a number of Data Guard environments had stopped and archive logging not being applied.

As the logs not being shipped the recovery area on the primary slowly filled up. The RMAN backup was unable to delete the archive logs as they not been applied on the DG side.

The decision was made to increase the RECO area in Oracle Cloud so at least the archiving was able to continue and the environments were able to be used. 

Rebooted the two DG servers so the physical standby servers were available.

We checked the standby side to see what the archive gap was - 

SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE#
FROM V$ARCHIVE_GAP;

This identified logs missing from instance 1 and instance 2 -

Logging into RMAN on the primary, restored the missing logs - 

RUN
   RESTORE ARCHIVELOG FROM SEQUENCE 12562 UNTIL SEQUENCE 12598 THREAD 1;
}
 
RUN {
   RESTORE ARCHIVELOG FROM SEQUENCE 11987 UNTIL SEQUENCE 12017 THREAD 2;
}

After, to get DataGuard to work, we stop / started the apply and transport - 

edit database DBG2P_wnn_lhr set state='APPLY-OFF';               --dataguard 
edit database DBG2P_qwg_lhr set state='TRANSPORT-OFF';   --primary
 
edit database DBG2P_qwg_lhr set state='TRANSPORT-ON';     --primary
edit database DBG2P_wnn_lhr set state='APPLY-ON';            --dataguard

Once working the data log started dropping and checked using -

DGMGRL> validate database verbose db_name

db_name - replace as appropriate.