ORACLE 10g

1

• ORACLE 10g
• DATA GUARD BROKER
• Ritesh Chhajer
• Sr. Oracle DBA

2
Agenda

• DG Broker Concepts Advantages
• Setup using CLI(DGMGRL)
• Useful broker commands
• Switchover

3
Concepts

• Any Data Guard configuration consists of one
  primary database and up to nine standby
  databases.
• The Data Guard broker logically groups these
  primary and standby databases into a broker
  configuration so as to manage and monitor them
  together as an integrated unit.
• Data Guard broker is a centralized framework to
  manage entire Data Guard configuration through a
  client connection to any database in the
  configuration.
• Accessed either locally or remotely using either
  of the two clients CLI interface(DGMGRL) or the
  Data Guard page from GUI( OEM Grid Control )
• DGMGRL does not have the ability to create
  standby (GUI can do it). CLI is used mostly for
  configuration and management.
• Easy switchover/failover with one command thereby
  minimizing overall downtime associated with the
  planned/unplanned outage
• Integrated with CRS so that database role changes
  occur smoothly and seamlessly.
• Instead of managing primary and standby databases
  with various SQLPlus statements, broker provides
  a single unified configuration

4
DMON

• Data Guard monitor process (DMON) runs for every
  database instance that is managed by the broker
  and maintains the broker configuration in a
  binary configuration file
• Whenever a broker command is issued, DMON
  process
• Carries out the request on primary database
• Coordinates with DMON process for each of the
  other databases
• Updates its local configuration file
• Communicates with DMON process for each of the
  other databases to update their copies of the
  configuration file

5
Prerequisites

• Set up following parameters on primary and
  standby
• DG_BROKER_STARTTRUE
• DG_BROKER_CONFIG_FILE1ltPATHgt
• DG_BROKER_CONFIG_FILE2ltPATHgt
• LOCAL_LISTENER
• GLOBAL_DBNAME in listener.ora as
  db_unique_name_DGMGRL.db_domain
• To enable DGMGRL to restart instances, a service
  with a specific name must be statically
  registered with the local listener of each
  instance.
• For RAC, ensure dg_broker_config_files are on
  shared storage and accessible to all instances.
• START_OPTIONS for RAC database must be set to
  MOUNT in OCR using SRVCTL (For switchover/Failover
  operations for broker and CRS to coordinate
  while restarting instances and database role
  reversal)
• SPFILE must be used

6
Switchover

• Once SWITCHOVER is issued, the broker does the
  following
• Verifies state of primary and standby database
  are enabled and in ONLINE state
• Shuts down all RAC instances except one
• Switches roles between the primary and standby
  databases.
• Updates the broker configuration file to record
  the changes in roles
• Restarts the new standby database and any RAC
  instances that were shutdown prior to switchover.
• Restarts the new primary database, opens it in
  read-write mode, and starts log transport
  services transmitting redo data to the archived
  redo log files for standby database
• After switchover completes, the overall Data
  Guard protection mode remains at the same
  protection level as it was before the switchover.
• For DGMGRL to restart instances automatically,
  you must connect to the database as SYSDBA using
  the username and password specified in the remote
  password file before beginning the switchover.

7

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