fast_start failover tips

Question:  I want to deploy fast_start_failover, but I don't understand the steps for enabling fast_start_failover and verifying that fast_start_failover is working?  Can you help?

Answer:  By Laurent Schneider:  Prerequisites for fast_start_failover include:

• Enable fast_start failover you must have a working set of primary / standby databases.
  
• Both databases must be in flashback mode.
  
• Verify your Data Guard configuration with OEM.  You will need to review your Data Guard property.

lsc01 my primary, lsc05 my standby

edit database lsc01 set LogXptMode='SYNC';
edit database lsc01 set FastStartFailoverTarget= 'lsc05'
edit database lsc05 set LogXptMode='SYNC';
edit database lsc05 set FastStartFailoverTarget= 'lsc01'
EDIT CONFIGURATION SET PROTECTION MODE AS MaxAvailability;

Next, you need to start the fast_start failover observer  (usog th Data Guard dgmgrl -silent "start observer" command.  You submit this dgmgrl command in the background with the nohup command so it is always running as a daemon process.:

nohup dgmgrl -silent sys/*** "start observer" &

Now that we have the fast_start failover prerequisites, enable fast_start failover in dgmgrl:

DGMGRL> enable fast_start failover

Before you switch, check the listener.ora is correctly configured :

SID_LIST_LISTENER=
  (SID_LIST=
    (SID_DESC=
      (GLOBAL_DBNAME=LSC01_DGMGRL.example.com)
      (SID_NAME=LSC01)
      (ORACLE_HOME=/u01/app/oracle/product/11.2.0/dbhome_1)
    )
    (SID_DESC=
      (GLOBAL_DBNAME=LSC05_DGMGRL.example.com)
      (SID_NAME=LSC05)
      (ORACLE_HOME=/u01/app/oracle/product/11.2.0/dbhome_1)
    )
  )

LISTENER =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = precision.example.com)(PORT = 1521))
  )

UPDATE:  FOR 11GR2

Alternatively in 11gR2 and beyond, you can set the Data Guard property StaticConnectIdentifier to use a SID instead of   service name :

edit database lsc05 set property StaticConnectIdentifier=
  '(DESCRIPTION=
    (ADDRESS=(PROTOCOL=tcp)(HOST=precision.example.com)(PORT=1521))
    (CONNECT_DATA=(SID=LSC05)))';

edit database lsc01 set property StaticConnectIdentifier=
  '(DESCRIPTION=
    (ADDRESS=(PROTOCOL=tcp)(HOST=precision.example.com)(PORT=1521))
    (CONNECT_DATA=(SID=LSC01)))';

Ok, let’s see how fast I can switch

$ time dgmgrl -silent sys/*** "switchover to lsc05"
Performing switchover NOW, please wait...
New primary database "lsc05" is opening...
Operation requires shutdown of instance "LSC01" on database "lsc01"
Shutting down instance "LSC01"...
ORACLE instance shut down.
Operation requires startup of instance "LSC01" on database "lsc01"
Starting instance "LSC01"...
ORACLE instance started.
Database mounted.
Switchover succeeded, new primary is "lsc05"

real    1m10.685s
user    0m0.052s
sys     0m0.109s

About one minute. most of the time was spent restarting the original primary as a standby, the primary was already available for queries after about 20 seconds.

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