ORA-16795: the standby database needs to be re-created

DB CONFIGURATION

2 node primary database

2 node standby database

Fast_Start FailOver(observer)- Enabled

BHU_A è Primary database

BHU_B è standby database

n  Due to the network issues, FSFO failover the standby database (BHU_B) as a new primary and old primary database (BHU_A) is in the mount stage.

oracle BHU bhuora001> dgmgrl

DGMGRL for Linux: Version 11.2.0.3.0 - 64bit Production

Copyright (c) 2000, 2009, Oracle. All rights reserved.

Welcome to DGMGRL, type "help" for information.

DGMGRL> connect sys /xxxxxxxxxxxxxx

Connected.

DGMGRL> show configuration

Configuration - DG_BHU

  Protection Mode: MaxAvailability

  Databases:

    BHU_B - Primary database

      Warning: ORA-16817: unsynchronized fast-start failover configuration

    BHU_A - (*) Physical standby database (disabled)

      ORA-16795: the standby database needs to be re-created

Fast-Start Failover: ENABLED

Configuration Status:

WARNING

n  We check the flashback enabled option on both old & new primary. We are showing the output of new primary database

SQL> select flashback_on from v$database;

FLASHBACK_ON

------------------

YES

n  On the NEW PRIMARY SITE; check when the conversion happened(standby to primary) and you can see the time by looking to scn_to_timestamp conversion.

SQL> SELECT TO_CHAR(STANDBY_BECAME_PRIMARY_SCN) FROM V$DATABASE;

TO_CHAR(STANDBY_BECAME_PRIMARY_SCN)

----------------------------------------

12788498729592

SQL> SELECT SCN_TO_TIMESTAMP(12788498729592) from dual;

SCN_TO_TIMESTAMP(12788498729592)

---------------------------------------------------------------------------

08-AUG-13 22.04.00.000000000

On the OLD PRIMARY DATABASE(BHU_A). Check the status of database

SQL> select name,open_mode,database_role from gv$database;

NAME      OPEN_MODE            DATABASE_ROLE

--------- -------------------- ----------------

BHU    MOUNTED              PRIMARY

SQL> select flashback_on from v$database;

FLASHBACK_ON

------------------

YES

n When we try to check  CURRENT_SCN number on the old primary and it has displayed as “0”

SQL> select current_scn from v$database;

CURRENT_SCN

-----------

          0

Now, We are converting the old primary database as a NEW STANDBY DATABASE

n  We are mounting the database first

SQL> shutdown immediate;

ORA-01109: database not open

Database dismounted.

ORACLE instance shut down.

SQL> startup mount;

ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance

ORACLE instance started.

Total System Global Area 2271580160 bytes

Fixed Size                  2230352 bytes

Variable Size            1191184304 bytes

Database Buffers         1073741824 bytes

Redo Buffers                4423680 bytes

Database mounted.

n  We have identified the failover time from the new database. so we will use that time to flashback the old primary database; we have add 20 further to actual time.

SQL> FLASHBACK DATABASE TO TIMESTAMP to_timestamp('2013-08-08 21:50:00', 'YYYY-MM-DD HH24:MI:SS');

Flashback complete.

n  We are checking the current role before converting the old primary to new standby database.

SQL> select name,open_mode,database_role from v$database;

NAME      OPEN_MODE            DATABASE_ROLE

--------- -------------------- ----------------

BHU    MOUNTED              PRIMARY

n  Converting database to standby database.

SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;

Database altered.

n  We are checking the current role after converting the old primary to new standby database.

SQL> select name,open_mode,database_role from v$database;

select name,open_mode,database_role from v$database

                                         *

ERROR at line 1:

ORA-01507: database not mounted

n  After converting the database; database will go to nomount stage; so we have to stop & start the database.

SQL> shutdown immediate;

ORA-01507: database not mounted

ORACLE instance shut down.

SQL> startup mount;

ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance

ORACLE instance started.

Total System Global Area 2271580160 bytes

Fixed Size                  2230352 bytes

Variable Size            1191184304 bytes

Database Buffers         1073741824 bytes

Redo Buffers                4423680 bytes

Database mounted.

SQL> select name,open_mode,database_role from v$database;

NAME      OPEN_MODE            DATABASE_ROLE

--------- -------------------- ----------------

BHU    MOUNTED              PHYSICAL STANDBY

n  We could see the current status of the old primary as new standby database.

n  Now we are login to the dg broker to enable the new standby database

DGMGRL> enable database 'BHU_A';

Enabled.

n  Once enabled, oracle will take some time to apply the logs till the current time

DGMGRL> show configuration;

Configuration - DG_BHU

  Protection Mode: MaxAvailability

  Databases:

    BHU_B - Primary database

      Warning: ORA-16817: unsynchronized fast-start failover configuration

    BHU_A - (*) Physical standby database

      Warning: ORA-16817: unsynchronized fast-start failover configuration

Fast-Start Failover: ENABLED

Configuration Status:

WARNING

n  Now primary database & standby database are in sync.

DGMGRL> show configuration;

Configuration - DG_BHU

  Protection Mode: MaxAvailability

  Databases:

    BHU_B - Primary database

    BHU_A - (*) Physical standby database

Fast-Start Failover: ENABLED

Configuration Status:

SUCCESS