You have done a failover to your Standby database so it becomes the new Primary. It may be possible to convert the old Primary into a Standby database now instead of having to do a time consuming duplicate again. The old Primary must have been running in flashback mode before the failover. The playground:
DGMGRL> show configuration; Configuration - myconf Protection Mode: MaxAvailability Members: prima - Primary database physt - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS (status updated 36 seconds ago) SYS@prima > host echo kaputt > /home/oracle/prima/users01.dbf SYS@prima > select * from scott.emp; select * from scott.emp * ERROR at line 1: ORA-01115: IO error reading block from file (block # ) ORA-01110: data file 4: '/home/oracle/prima/users01.dbf' ORA-27072: File I/O error Additional information: 4 Additional information: 130
I did just cause a damage on my Primary database in order to have a reason to failover. I took backups on the Primary previously and could do restore and recovery instead of the failover. But failover ist way faster. After all, that is what we have the Standby for 🙂
[oracle@uhesse scripts]$ dgmgrl sys/oracle@physt DGMGRL for Linux: Version 18.104.22.168.0 - 64bit Production Copyright (c) 2000, 2013, Oracle. All rights reserved. Welcome to DGMGRL, type "help" for information. Connected as SYSDBA. DGMGRL> failover to physt; Performing failover NOW, please wait... Failover succeeded, new primary is "physt"
Took less than 10 seconds. Now I want a Standby for my new Primary. If the old Primary has had a power outage only, the Reinstate could be done immediately. But here, one datafile is damaged. Reinstate needs intact datafiles. Therefore first a restore, then reinstate:
[oracle@uhesse scripts]$ rman target sys/oracle@prima Recovery Manager: Release 22.214.171.124.0 - Production on Thu Sep 15 16:58:24 2016 Copyright (c) 1982, 2014, Oracle and/or its affiliates. All rights reserved. connected to target database (not started) RMAN> startup mount Oracle instance started database mounted Total System Global Area 838860800 bytes Fixed Size 2929936 bytes Variable Size 490736368 bytes Database Buffers 339738624 bytes Redo Buffers 5455872 bytes RMAN> restore datafile 4; Starting restore at 2016-09-15 16:59:04 using target database control file instead of recovery catalog allocated channel: ORA_DISK_1 channel ORA_DISK_1: SID=176 device type=DISK channel ORA_DISK_1: starting datafile backup set restore channel ORA_DISK_1: specifying datafile(s) to restore from backup set channel ORA_DISK_1: restoring datafile 00004 to /home/oracle/prima/users01.dbf channel ORA_DISK_1: reading from backup piece /home/oracle/fra/PRIMA/backupset/2016_09_15/o1_mf_nnndf_TAG20160915T163533_cxomgq0q_.bkp channel ORA_DISK_1: piece handle=/home/oracle/fra/PRIMA/backupset/2016_09_15/o1_mf_nnndf_TAG20160915T163533_cxomgq0q_.bkp tag=TAG20160915T163533 channel ORA_DISK_1: restored backup piece 1 channel ORA_DISK_1: restore complete, elapsed time: 00:00:01 Finished restore at 2016-09-15 16:59:05 RMAN> select flashback_on from v$database; FLASHBACK_ON ------------------ YES RMAN> exit Recovery Manager complete. [oracle@uhesse scripts]$ dgmgrl sys/oracle@physt DGMGRL for Linux: Version 126.96.36.199.0 - 64bit Production Copyright (c) 2000, 2013, Oracle. All rights reserved. Welcome to DGMGRL, type "help" for information. Connected as SYSDBA. DGMGRL> show configuration; Configuration - myconf Protection Mode: MaxAvailability Members: physt - Primary database Warning: ORA-16629: database reports a different protection level from the protection mode prima - Physical standby database (disabled) ORA-16661: the standby database needs to be reinstated Fast-Start Failover: DISABLED Configuration Status: WARNING (status updated 17 seconds ago) DGMGRL> reinstate database prima; Reinstating database "prima", please wait... Reinstatement of database "prima" succeeded DGMGRL> show database prima; Database - prima 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: 44.00 KByte/s Real Time Query: OFF Instance(s): prima Database Status: SUCCESS
Optionally, I may switch back now:
DGMGRL> switchover to prima; Performing switchover NOW, please wait... Operation requires a connection to instance "prima" on database "prima" Connecting to instance "prima"... Connected as SYSDBA. New primary database "prima" is opening... Operation requires start up of instance "physt" on database "physt" Starting instance "physt"... ORACLE instance started. Database mounted. Switchover succeeded, new primary is "prima" DGMGRL> show configuration; Configuration - myconf Protection Mode: MaxAvailability Members: prima - Primary database physt - Physical standby database Fast-Start Failover: DISABLED Configuration Status: SUCCESS (status updated 40 seconds ago)
This is one reason why we recommend that you turn on flashback for the databases that are part of a Data Guard configuration. As always: Don’t believe it, test it 🙂
#1 von alexandruneda am September 21, 2016 - 15:38
This is a great article, thank you Uwe!
I was just testing a 12c failover with the broker and was wondering how will I convert the old primary to standby 🙂
#2 von rajat sharma am September 24, 2016 - 02:37
Could you please explain the requirement of no of days/hrs flash back needed to perform below activity
#3 von Uwe Hesse am September 27, 2016 - 16:52
You wouldn’t need that much flashback logs unless the old primary is not up for a longer period of time after the failover. Suppose you did the failover one hour ago and the old primary is still up. Then db_flashback_retention_target should be at least 60 for the reinstate to work.
#4 von Yaseen am Februar 14, 2018 - 06:28
This is a great article, thank you Uwe.
This method will work for 188.8.131.52 as well ?
Would you please explain the method if flashback not enabled ?
Thanks in advance.