Data Guard switchover with dgmgrl Oracle Tips by Burleson Consulting March 11, 2010

Question:  I want to use the switchover command with dgmgrl to switch over to my Data Guard Standby database.  How to I configure my tnsnames with failover for Data Guard switchover dgmgrl command?

db1 =
(DESCRIPTION =
   (ADDRESS_LIST =
     (FAILOVER = ON)
       (ADDRESS = (PROTOCOL = TCP)(HOST = host1(PORT = 1521))
       (ADDRESS = (PROTOCOL = TCP)(HOST = host2)(PORT = 1521)
   )
)

Answer:  For complete details on doing a Data Guard switchover, see the book “Oracle Data Guard” by Bipul Kumar.  There are many examples, and Ritesh Chhajer offers this example of doing a Data Guard switchover using dgmgrl:

1. Ensure SPFILE is used

SQL> sho parameter spfile

2. Verify dmon process is running and broker parameters viz. DG_BROKER_START is set to TRUE and DG_BROKER_CONFIG_FILEn are set correctly

SQL> sho parameter broker
$ps -ef|grep dmon|grep -v grep

3. Check if LOCAL_LISTENER is set(This is needed only if you are non-default port other than 1521)

DGMGRL> show instance 'TESTPRIR1' 'LocalListenerAddress';

4. Verify if GLOBAL_DBNAME in listener.ora is set correctly to
 <<db_unique_name>>_DGMGRL.<<db_domain>>

Example listener.ora:

SID_LIST_LISTENER_TESTPRIR1 =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /apps/oracle/product/10g/db)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (SID_NAME = TESTPRIR1)
      (GLOBAL_DBNAME = TESTPRI_DGMGRL)
      (ORACLE_HOME = /apps/oracle/product/10g/db)
    )
  )

Note: In the above case, db_domain was null.

5. Verify if START_OPTIONS is set to MOUNT in the OCR

$ srvctl config database -d TESTPRI -a
testprir1 TESTPRIR1 /apps/oracle/product/10g/db
testprir2 TESTPRIR2 /apps/oracle/product/10g/db
DB_NAME: null
ORACLE_HOME: /apps/oracle/product/10g/db
SPFILE: /n01/oradata/TESTPRI/spfileTESTPRI.ora
DOMAIN: null
DB_ROLE: PRIMARY
START_OPTIONS: MOUNT

6. Broker configuration is enabled and state of all members as intended is ONLINE

DGMGRL> show configuration

7. remote_login_passwordfile is set to 'EXCLUSIVE'

SQL> sho parameter remote_login_passwordfile

8. Verify TESTPRI and TESTDG tnspingable from both primary as well as standby and can connect to each other.

Let us do the actual switchover now. Since our primary database is RAC, let us also keep a watch on how the OCR status is changing.

9. Ensure <<db_unique_name>>_DGMGRL is part of service names otherwise post switchover, instances may have to be manually started

OCR Config before switchover:

[oracle@testprir1]/apps/oracle/product/10g/db/dbs% srvctl status database -d TESTPRI
Instance TESTPRIR1 is running on node testprir1
Instance TESTPRIR2 is running on node testprir2

[oracle@testprir1]/apps/oracle/product/10g/db/dbs% srvctl config database -d TESTPRI -a
testprir1 TESTPRIR1 /apps/oracle/product/10g/db
testprir2 TESTPRIR2 /apps/oracle/product/10g/db
DB_NAME: null
ORACLE_HOME: /apps/oracle/product/10g/db
SPFILE: /n01/oradata/TESTPRI/spfileTESTPRI.ora
DOMAIN: null
DB_ROLE: PRIMARY
START_OPTIONS: MOUNT

Broker config before switchover:

DGMGRL> show configuration;

Configuration
  Name:            DG_TEST
  Enabled:         YES
  Protection Mode: MaxPerformance
  Databases:
    TESTPRI - Primary database
    TESTDG  - Physical standby database

Current status for "DG_TEST":
SUCCESS

Switchover Now:

DGMGRL> switchover to 'TESTDG';