2026-03-12 21:01:38

tiddlywiki/Dataguard - sync using incremental backup.md

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+# Dataguard configuration
+
+	DGMGRL> show configuration
+
+	Configuration - asty
+
+	  Protection Mode: MaxPerformance
+	  Members:
+	  astyprd - Primary database
+	    astydrp - Physical standby database 
+
+
+	DGMGRL> show database 'astydrp'
+
+	Database - astydrp
+
+	  Role:                PHYSICAL STANDBY
+	  Intended State:      APPLY-ON
+	  Transport Lag:       0 seconds (computed 1 second ago)
+	  Apply Lag:           0 seconds (computed 1 second ago)
+	  Average Apply Rate:  803.00 KByte/s
+	  Real Time Query:     OFF
+	  Instance(s):
+	    ASTYDRP
+
+# Simulate a gap
+
+Stop the standby database. 
+
+On primary, switch 3-4 times the archivelog on primary and delete all archived logs:
+
+	SQL> alter system archive log current;
+	RMAN> delete noprompt force archivelog all;
+
+To complicate the situation, add 2 new datafile and create a new tablespace on primary.
+
+	SQL> alter tablespace SYSTEM add datafile size 10M autoextend OFF;
+	SQL> alter tablespace SYSAUX add datafile size 10M autoextend OFF;
+	SQL> create tablespace NAL_HUTTA datafile size 10M autoextend ON next 10M;
+
+Repeat switch/delete archivelog operation on primary:
+
+	SQL> alter system archive log current;
+	RMAN> delete noprompt force archivelog all;
+
+Start the standby database in **MOUNT** mode, let it trying to resolve the gap and check the status of the syncronisation.  
+On primary:
+
+	alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';
+	set lines 200
+
+	select THREAD#, max(SEQUENCE#), max(FIRST_TIME),max(NEXT_TIME),max(COMPLETION_TIME) 
+	from gv$archived_log group by THREAD#;
+
+On standby:
+
+	alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';
+	set lines 200
+
+	select THREAD#, max(SEQUENCE#), max(FIRST_TIME),max(NEXT_TIME),max(COMPLETION_TIME) 
+	from gv$archived_log
+	where APPLIED='YES' group by THREAD#;
+
+
+# Syncronize the standby
+
+Cancel **MRP** on standby:
+
+	DGMGRL> edit database 'astydrp' set STATE='LOG-APPLY-OFF';
+
+Try to recover the standby and note down the required `SCN`:
+
+	SQL> recover standby database;
+
+Normaly it should be the same as:
+
+	SQL> select 1+CURRENT_SCN from v$database;
+
+On primary, identify all datafiles created after this `SCN`; in my example `SCN=5681090`
+
+	SQL> select FILE#,NAME from v$datafile where CREATION_CHANGE# >= 5681090;
+
+Backup datafiles and generate a new standby controlfile:
+
+	run{
+	  set nocfau;
+	  allocate channel ch01 device type disk format '/mnt/yavin4/tmp/_oracle_/orabackup/temp/%d_%U_%s_%t.bck';
+	  allocate channel ch02 device type disk format '/mnt/yavin4/tmp/_oracle_/orabackup/temp/%d_%U_%s_%t.bck';
+	  allocate channel ch03 device type disk format '/mnt/yavin4/tmp/_oracle_/orabackup/temp/%d_%U_%s_%t.bck';
+	  allocate channel ch04 device type disk format '/mnt/yavin4/tmp/_oracle_/orabackup/temp/%d_%U_%s_%t.bck';
+	  backup as compressed backupset datafile 17,18,19;
+	  release channel ch01;
+	  release channel ch02;
+	  release channel ch03;
+	  release channel ch04;
+	  allocate channel ch01 device type disk format '/mnt/yavin4/tmp/_oracle_/orabackup/temp/%d_%U_%s_%t.ctl';
+	  backup current controlfile;
+	  release channel ch01;
+	}
+
+
+Restart the standby in mode **NOMOUNT** and restore the standby controfile:
+
+	RMAN> restore standby controlfile from '/mnt/yavin4/tmp/_oracle_/orabackup/temp/ASTY_0l1678fs_21_1_1_21_1113825788.ctl';
+
+Alternatively, you can restore the standby controfile from active database:
+
+	RMAN> restore standby controlfile from service ASTYPRD_DGMGRL;
+
+Mount the standby database:
+
+	RMAN> alter database mount;
+
+Restore and new datafiles:
+
+	RMAN> restore datafile 17,18,19;
+
+Catalog recovery area and old standby datafiles:
+
+	RMAN> catalog start with '/data/ASTYDRP' noprompt;
+	RMAN> catalog start with '/fra/ASTYDRP' noprompt;
+
+At this moment, because of fresh restored controlfile, Oracle see the datafiles as datafile copy:
+
+	RMAN> list datafilecopy all;
+
+Switch database to copy:
+
+	RMAN> switch database to copy;
+
+
+To recover standby using *from SCN* backupset, we can proceed from active database or using physical backupset:
+
+	rman auxiliary /
+	run {
+	  allocate channel pri1 device type DISK;
+	  allocate channel pri2 device type DISK;
+	  allocate channel pri3 device type DISK;
+	  allocate channel pri4 device type DISK;
+	  recover database from service ASTYPRD_DGMGRL using compressed backupset section size 8G;
+	}
+
+Clear standby redolog:
+
+	SQL> select 'ALTER DATABASE CLEAR LOGFILE GROUP '||GROUP#||';' from v$standby_log;
+
+Enable **MRP**:
+
+	DGMGRL> edit database 'astydrp' set STATE='ONLINE';