Opening a DR database in read/write mode temporarily using Snapshot Standby

Opening  a DR database
in read write mode using Snapshot Standby method
Objective of this document is to convert a DR database (Mount state) into
Read Write mode using Snapshot standby method and restoring it back to sync it
up with the PRIMARY database.
DR Environment
The I****01 has a two node clustered
DR database as follows,
NAME     
DB_UNIQUE_NAME                
OPEN_MODE
——— ——————————
——————–
I****01   DRI****01                      MOUNTED
I****01   DRI****01                      MOUNTED
INSTANCE_NAME   
STATUS       HOST_NAME
—————- ————
——————————–
I****011        
MOUNTED      of90.egan.server.com
I****012        
MOUNTED      of91.egan.server.com
The
flashback mode is disabled in I****01 database.
The
Flashback mode has to be enabled to restore the DR after application
installation.
Steps to enable the flashback mode in both the Primary and DR
I****01 database.
1.       
Enabling Flashback in DR database.
a.       
Cancel the recovery in the standby database.
STANDBY>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE
CANCEL;
b.       
Then activate the FLASHBACK on the standby
database.
STANDBY> alter system set db_flashback_retention_target=1440
scope=both;
### retention value varies depending on
the requirement.
STANDBY>ALTER DATABASE FLASHBACK ON;
c.       
Verify the flashback mode,
SQL> select flashback_on from v$database;
2.       
Enabling Flashback in the Primary database.
a.       
Activate the FLASHBACK on the PRIMARY
database.
PRIMARY> alter system set
db_flashback_retention_target=1440 scope=both;
####
retention value varies depending on the requirement.
PRIMARY> alter database flashback on;
b.       
Verify the flashback mode,
SQL> select flashback_on from v$database;
Once
the flashback mode is enabled, we shall go ahead and bring the DR in the read
write mode.
Steps to open the DR database in Read/Write mode using
Snapshot Standby
a.       
Stop the recovery in the DR database.
STANDBY>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE
CANCEL;
b.       
Check The MRP status,
STANDBY>select
PROCESS,CLIENT_PROCESS,THREAD#,SEQUENCE#,BLOCK# from v$managed_standby where
process = ‘MRP0′ or client_process=’LGWR’;
                                                                                                                        (or)
host#     ps –ef|grep
–imrp
c.       
Bring down all instances except oneon which
we will be using the conversion commands, and ensure the DR database is in
mount state
d.       
Convert the Physical standby DR to Snapshot
standby DR,
STANDBY>ALTER DATABASE CONVERT TO SNAPSHOT STANDBY;
e.       
The DR database will be dismounted after the
conversion, so start it.
STANDBY>startup;
f.        
The DR will be open in Read/Write mode now.
Steps to convert the Snapshot standby DR to Physical Standby
DR
a.       
Shutdown all the instances except one on
which we will be using the conversion commands.
b.       
Ensure that the database is mounted.
c.       
Do the conversion of snapshot standby
database to physical standby database.
STANDBY>ALTER DATABASE CONVERT TO PHYSICAL STANDBY;
d.       
Change back the DR to Physical Standby
database,
STANDBY>ALTER DATABASE CONVERT TO PHYSICAL STANDBY;
e.       
Bounce the DR database and bring them to
mount,
STANDBY>shutdown immediate
STANDBY>startup mount
f.        
Enable the log shipping in the primary
database,
PRIMARY>ALTER SYSTEM SET
LOG_ARCHIVE_DEST_STATE_2=ENABLE;
g.       
Start the MRP in the DR database,
STANDBY>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE
USING CURRENT LOGFILE DISCONNECT FROM SESSION;
  • January 17, 2017 | 23 views
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