- \n
- DGMGRL command interface<\/li>\n
- Enterprise Manager Cloud Control<\/li>\n<\/ul>\n<\/li>\n
- Server Side<\/li>\n<\/ol>\n
- \n
- \n
- \n
- DMON (Data Guard Monitor) Process<\/li>\n
- Configuration file<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
The working architecture of Data Guard Broker is as follows;<\/p>\n
![\"\"](\"https:\/\/dbtut.com\/wp-content\/uploads\/2020\/12\/img_5fd7370f2ef50.png\")
<\/p>\nIn summary; All commands run via DGMGRL or Cloud Control are written to the Configuration files in each instance as a result of the communication of all DMON processes in the environment with each other. Thus, the entire Data Guard Environment can be managed from a single center. It can be installed in a completely separate instance or via Primary Database.<\/p>\n
What is Data Guard Broker DMON Process?<\/h3>\n
DMON is a background process of Oracle that allocates approximately 50 Kb of space in SGA when Data Guard Broker is started.<\/p>\n
This process manages Data Guard by running on all instances including FAR SYNC instances in Data Guard configuration.<\/p>\n
When a transaction is made with Enterprise Manager Cloud Control or DGMGRL, the DMON process running locally communicates with DMON processes running on instances on the remote side and performs the operations.<\/p>\n
The DMON process is also responsible for monitoring whether the broker configuration is working properly and whether there are a consistent number of copies of the configuration file in all instances.<\/p>\n
Configuration files are created in default as 2 files under ORACLE_HOME\/dbs. These file’s names are dr1 <db_unique_name>.dat and dr2 <db_unique_name>.dat.<\/p>\n
The DMON process uses only one of these files. The other is for backup. In RAC systems, these files should be located in a shared area (ASM).<\/p>\n
In case of a problem, it creates trace and core files under ADR_HOME \/ trace in each instance.<\/p>\n
Comparison of managing Data Guard in the presence and absence of the broker can be seen in the figure below.<\/p>\n
![\"\"](\"https:\/\/dbtut.com\/wp-content\/uploads\/2020\/12\/img_5fd739b739d81.png\")
<\/p>\nBroker Startup Parameters<\/h3>\n
The database startup parameters controlled by the broker are below;<\/p>\n
- \n
- LOG_ARCHIVE_DEST_n<\/span><\/li>\n
- LOG_ARCHIVE_DEST_STATE_n<\/span><\/li>\n
- ARCHIVE_LAG_TARGET<\/span><\/li>\n
- PRESERVE_COMMIT_ORDER<\/span><\/li>\n
- RECORD_APPLIES_DDL<\/span><\/li>\n
- RECORD_SKIP_DDL<\/span><\/li>\n
- DB_FILE_NAME_CONVERT<\/span><\/li>\n
- LOG_ARCHIVE_FORMAT<\/span><\/li>\n
- LOG_ARCHIVE_MAX_PROCESSES<\/span><\/li>\n
- LOG_ARCHIVE_MIN_SUCCEED_DEST<\/span><\/li>\n
- LOG_ARCHIVE_TRACE<\/span><\/li>\n
- LOG_FILE_NAME_CONVERT<\/span><\/li>\n
- RECORD_SKIP_ERRORS<\/span><\/li>\n
- STANDBY_FILE_MANAGEMENT<\/span><\/li>\n
- MAX_EVENTS_RECORDED<\/span><\/li>\n
- MAX_SERVERS<\/span><\/li>\n
- MAX_SGA<\/span><\/li>\n
- PRESERVE_COMMIT_ORDER<\/span><\/li>\n
- RECORD_APPLIES_DDL<\/span><\/li>\n
- RECORD_SKIP_DDL<\/span><\/li>\n
- RECORD_SKIP_ERRORS<\/span><\/li>\n<\/ul>\n
As soon as it is decided to continue the management of Data Guard using the Broker, even a single SQL command should not be run on databases in the environment.<\/p>\n
Broker automatically uses the following Redo-Apply commands that are valid in Physical and Logical Standby.<\/p>\n
- \n
- ALTER DATABASE RECOVER MANAGED STANDBY DATABASE<\/li>\n
- ALTER DATABASE START LOGICAL STANDBY APPLY IMMEDIATE<\/li>\n<\/ul>\n
DGMRL Commands<\/h3>\n
The commands that can be run from DGMGRL are as follows;<\/p>\n
- \n
- ADD DATABASE: Adds a new standby database to the existing broker configuration<\/li>\n
- ADD FAR_SYNC: Adds an existing Far Sync instance to an Oracle Data Guard broker configuration<\/li>\n
- CONNECT: Connects to the specified database using the specified username<\/li>\n
- CONVERT DATABASE: Converts the specified database to either a snapshot standby database or a physical standby database<\/li>\n
- CREATE CONFIGURATION: Creates a broker configuration and adds a primary database to that configuration<\/li>\n
- DISABLE CONFIGURATION: Disables broker management of a configuration so that the configuration and all of its databases are no longer managed by the broker<\/li>\n
- DISABLE DATABASE: Disables broker management of the named standby database<\/li>\n
- DISABLE FAR_SYNC: Disables broker management of a Far Sync instance<\/li>\n
- DISABLE FAST_START FAILOVER: Disables fast-start failover<\/li>\n
- DISABLE FAST_START FAILOVER CONDITION: Allows a user to remove conditions for which a fast-start failover should be performed<\/li>\n
- EDIT CONFIGURATION (Property): Changes the value of a property for the broker configuration<\/li>\n
- EDIT CONFIGURATION (Protection Mode): Changes the current protection mode setting for the broker configuration<\/li>\n
- EDIT CONFIGURATION (RENAME): Changes the configuration name<\/li>\n
- EDIT CONFIGURATION RESET (Property): Resets the specified configuration property to its default value<\/li>\n
- EDIT DATABASE (Property): Changes the value of a property for the named database<\/li>\n
- EDIT DATABASE (Rename): Changes the name used by the broker to refer to the specified database<\/li>\n
- EDIT DATABASE (State): Changes the state of the specified database<\/li>\n
- EDIT DATABASE RESET (Property): Resets the specified property for the named database to its default value<\/li>\n
- EDIT FAR_SYNC: Changes the name, state, or properties of a Far Sync instance<\/li>\n
- EDIT FAR_SYNC RESET (Property): Resets the specified property for the named Far Sync instance to its default value<\/li>\n
- EDIT INSTANCE (AUTO PFILE): Sets the name of the initialization parameter file for the specified instance<\/li>\n
- EDIT INSTANCE (Property): Changes the value of a property for the specified instance<\/li>\n
- EDIT INSTANCE RESET (Property): Resets an instance-specific property for the specified instance(s) to its default value<\/li>\n
- ENABLE CONFIGURATION: Enables broker management of the broker configuration and all of its databases<\/li>\n
- ENABLE DATABASE: Enables broker management of the specified database<\/li>\n
- ENABLE FAR_SYNC: Enables broker management of the specified Far Sync instance<\/li>\n
- ENABLE FAST_START FAILOVER: Enables the broker to automatically fail over from the primary database to a target standby database<\/li>\n
- ENABLE FAST_START FAILOVER CONDITION: Allows a user to add conditions for which a fast-start failover should be performed<\/li>\n
- EXIT: Exits the Data Guard command-line interface<\/li>\n
- FAILOVER: Performs a database failover operation in which the standby database to which DGMGRL is currently connected fails over to the role of primary database<\/li>\n
- HELP: Displays online help for the Data Guard command-line interface<\/li>\n
- QUIT: Quits the Data Guard command-line interface<\/li>\n
- REINSTATE DATABASE: Reinstates the database after a failover<\/li>\n
- REMOVE CONFIGURATION: Removes the broker configuration and ends broker management of its members<\/li>\n
- REMOVE DATABASE: Removes the specified standby database from the broker configuration<\/li>\n
- REMOVE FAR_SYNC: Removes a Far Sync instance from an Oracle Data Guard broker configuration<\/li>\n
- REMOVE INSTANCE: Removes an instance from the broker configuration<\/li>\n
- SHOW CONFIGURATION: Displays information about the broker configuration<\/li>\n
- SHOW DATABASE: Displays information about the specified database<\/li>\n
- SHOW FAR_SYNC: Shows information about a Far Sync instance<\/li>\n
- SHOW FAST_START FAILOVER: Displays all fast-start failover\u2013related information<\/li>\n
- SHOW INSTANCE: Displays information about the specified instance<\/li>\n
- SHUTDOWN: Shuts down a currently running Oracle database<\/li>\n
- SQL: Allows you to enter SQL statements from the Data Guard command-line interface (DGMGRL)<\/li>\n
- START OBSERVER: Starts the observer<\/li>\n
- STARTUP: Starts an Oracle instance with the same options as SQL*Plus, including mounting and opening a database<\/li>\n
- STOP OBSERVER: Stops the observer<\/li>\n
- SWITCHOVER: Performs a switchover operation in which the current primary database becomes a standby database, and the specified standby database becomes the primary database<\/li>\n
- VALIDATE DATABASE: Performs a comprehensive set of database checks prior to a role change<\/li>\n<\/ul>\n
Data Guard Broker Requirements<\/h3>\n
- \n
- Databases in Data Guard Environment must be in Enterprise Edition.<\/li>\n
- In order to benefit from the features provided by 12c, COMPATIBLE parameter should be minimum 12.1.<\/li>\n
- Oracle Net Services (listener.ORA) settings must be made completely. In this context, a listener in the format db_unique_name_DGMGRL.db_domain must be created for each instance.<\/li>\n<\/ul>\n
Add an Instance to Data Guard Broker Environment<\/h3>\n
To add any instance in the Data Guard Broker Environment, the DG_BROKER_START start parameter must be set to TRUE.<\/p>\n
[Primary-1] SQL> show parameter dg_broker_start\r\n\r\nNAME TYPE VALUE\r\n------------------------------------ ----------- ------------------------------\r\ndg_broker_start boolean FALSE\r\n\r\n[Logical-1] SQL> show parameter dg_broker_start\r\n\r\nNAME TYPE VALUE\r\n------------------------------------ ----------- ------------------------------\r\ndg_broker_start boolean FALSE\r\n\r\n[Physical-1] SQL> show parameter dg_broker_start\r\n\r\nNAME TYPE VALUE\r\n------------------------------------ ----------- ------------------------------\r\ndg_broker_start boolean FALSE\r\n<\/pre>\n
Databases in the Broker Environment must be in MOUNT or OPEN mode.<\/p>\n
In RAC systems, the DG_BROKER_CONFIG_FILEn parameter should be configured to point to a shared area. In default the configuration files are under $ORACLE_HOME\/dbs. The files are in binary format. With the ALTER SYSTEM command, the default directory and name used are changed.<\/p>\n
[Primary-1] SQL> column name format a23\r\n[Primary-1] SQL> select max(length(value)) from v$parameter;\r\n\r\nMAX(LENGTH(VALUE))\r\n------------------\r\n 94\r\n\r\n[Primary-1] SQL> set linesize 500\r\n[Primary-1] SQL> column value format a94\r\n[Primary-1] SQL> select name, value from v$parameter where lower(name) like '%dg_broker_config_file%';\r\n\r\nNAME VALUE\r\n----------------------- ----------------------------------------------------------------------------------------------\r\ndg_broker_config_file1 \/u01\/app\/oracle\/product\/11.2.0\/db_1\/dbs\/dr1primary.dat\r\ndg_broker_config_file2 \/u01\/app\/oracle\/product\/11.2.0\/db_1\/dbs\/dr2primary.dat<\/pre>\n
Before starting the Data Guard Broker configuration, all LOG_ARCHIVE_DEST_n parameter that has the SERVICE attribute used in all instances in the environment is deleted.<\/p>\n
Another indispensable feature for Data Guard Broker is that all databases in the environment must be opened from SPFILE.<\/p>\n
The work done by the DMON process is in the same location as ALERT LOG, and for each instance it is named drc <$ ORACLE_SID> .log.<\/p>\n
<\/div>\n
- LOG_ARCHIVE_DEST_STATE_n<\/span><\/li>\n
- LOG_ARCHIVE_DEST_n<\/span><\/li>\n
- \n