(Oracle Call Interface) client that connects to the primary and target standby databases In this example, there are 3 ORLs with a max group# of 3. 4. Otherwise, they must be re-created from a copy of the new primary database. primary database. The string "NONAME" cannot be used as an observer name. Starts redo transport services to begin transmitting redo data to all bystander standby databases that were not disabled. Specifying Preferred Observers Based on Current Primary. Enable Fast-Start Failover Using Cloud Control. In addition, the primary database will shut down if it perceives a loss of connectivity for a period longer than FastStartFailoverThreshold seconds, if the FastStartFailoverPmyShutdown configuration property is set to TRUE. Group definition this section is optional. Step-by-step instructions for manual reinstatement are described in Reenabling Disabled Databases After a Role Change. https://www.facebook.com/dbahariprasath/? STANDBY>connect /@STAN as sysdba switch does not happen until the next time the primary contacts the target standby, If there is only one standby database in the configuration, you can skip this step and continue with Task 3. You want to prevent fast-start failover from occurring because the primary database will resume service soon. Failovers become routine. This guide uses the naming convention of appending an underscore followed by a letter to the db_name to create the db_unique_name. Errors occurring for any other configuration members will not impede the switchover. It will return PRIMARY, Figure 6-1 shows the relationships between the primary database, target standby database, and observer during fast-start failover: Before Fast-Start Failover: Oracle Data Guard is operating in a steady state, with the primary database transmitting redo data to the target standby database and the observer monitoring the state of the entire configuration. However, if you want the observer to reconnect to the primary database periodically as a means of testing the health of the network connection to the primary, then use the ObserverReconnect configuration property. If a fast-start failover was initiated because the primary database had crashed or lost connectivity with the master observer and target standby database, then the master observer automatically attempts to reinstate the former primary database as a standby database, if the FastStartFailoverAutoReinstate configuration property is set to TRUE. The command SHOW OBSERVER provides detailed information about registered observers. Transitions the target standby database into the primary database role, as follows: Changes the role of the database from standby to primary. 1,000,000 block changes on a small set of blocks generates less Flashback Database history than 1,000,000 changes on a larger set of blocks. Commands For Managing Observers on Multiple Configurations. Fast-Start Failover in Oracle 11g Data Guard - Database Journal fast-start failover when: A network outage isolates the primary database from the observer and the target standby database before conditions exist that warrant a failover. On the Oracle Data Guard Overview page, click Database must be reinstated. Were sorry. See the Oracle Maximum Availability Architecture technical briefs at: When setting the FastStartFailoverLagLimit configuration property, consider these tradeoffs between performance and potential data-loss: A low lag limit will minimize data loss but may impact the performance of the primary database. In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. The subdirectories that DGMGRL creates under this directory will also have the Examples of starting observers using DGMGRL are included in Scenario 6: Enabling Fast-Start Failover and Starting the Observer. Starting with 11 is purely cosmetic - it allows new ORL groups to be added later while keeping their group# in the same sequence as the existing ORLs. When this property is set to the default value of 0, it prevents the observer from periodically establishing a new connection with the primary database. Note that this does not guarantee no data will be lost. Any broker configuration name that is referred to must exist in the configuration declaration section. It provides a way to quickly restore a database to a previous point in time or SCN using on-disk data structures called flashback logs. file (fsfo.dat). primary. The new primary database starts transmitting redo data to the new standby database. If the primary or target standby databases lose connections to all backup observers, then the broker does not try to nominate a backup observer as the new master observer, and the broker reports that the configuration is not observed. The configuration must be operating in either maximum availability mode or maximum performance mode in order to be able to switch over to a logical standby database. specified, the file is stored in an appropriate directory under the broker's RMAN will copy the spfile from the primary, so this init.ora file is only needed during the first phase of the duplication. FSFO builds upon a number of other Oracle technologies and features such as Data Guard, Flashback Database, and Data Guard Broker. Oracle FAN with Oracle Data Guard but without using Oracle Grid/ RAC Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. The procedure for using RMAN to create a standby database is fully explained in Appendix F of Oracle Oracle Data Guard Concepts and Administration document (10g Rel 2 and 11g Rel 1). The configuration and database status report the same error messages as are returned when there is only one registered observer. In maximum protection mode, an automatic failover is always possible because the LinkedIn:https://www.linkedin.com/in/hari-prasath-aa65bb19/ Oracle Database 11g FSFO adds support for Maximum Performance mode (async redo transfer), providing the flexibility to trade durability for performance. 2) Switchover/Failover option is disabled on Enterprise Manager.What are the steps to enable it so that I can do Switchover/Failover operation using OEM. The broker allows a complete failover to proceed as long as there are no errors present on the standby database that you selected to participate in the failover. Notice that the former primary is now disabled. The following sections describe how to reinstate or reenable a database. If both HVR and Data Guard were running without latency or if no changes were made to the source database at the time of the failover, it can be assumed that all databases are synced and the no extra steps are necessary; the steps for Graceful Failover can be followed. Data Guard Physical Standby Setup in Oracle Database 11g Release 2 Set this property for the primary and target standby database if you want the observer to use a different connect identifier than that used to ship redo data (that is, the connect identifier specified by the DGConnectIdentifier property). SQL>connect /@STAN as sysdba Manual failover gives you control over exactly when a failover occurs and to which target standby database. See Oracle Enterprise Manager Command Line Interface. The old Primary must have been running in flashback mode before the failover. The minimum value is 100 milliseconds. Without the credentials, Broker will complete the role transition, but will leave the databases in need of a manual restart. The primary database can be opened even if there is no acknowledgement from the observer or target standby. To achieve This can be avoided by first disabling fast-start failover with the FORCE option on the target standby. A value of TRUE helps to ensure that an isolated primary database cannot satisfy user queries. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. The most common problems are mismatched Data Guard protection modes and LogXptMode properties and forgetting to enable Flashback Database on the primary or standby. When a fast-start failover occurs because either a user configurable fast-start failover condition is detected or an application initiates a fast-start failover by calling the DBMS_DG.INITIATE_FS_FAILOVER function, the former primary database is always shut down and never automatically reinstated. Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. Displays the current fast-start failover mode. Note that the database will not open at this point. The target standby database has contact with the primary database. 1. Prepare the primary database in advance for its possible future role as a standby database in the context of the overall protection mode (see Managing Data Protection Modes). In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. The time interval starts when the observer first loses its connection to the primary database. PeopleSoft can be configured for Active Data Guard. How to Test Data Guard Fast-Start Failover by Shutting Down Primary In They must be re-created before they can serve as standby to the new primary database. They can all be done at the same time in a single bounce. files include the observer configuration file (observer.ora), observer log Let's run the command on the primary database to validate if the environments are ready for the role transition : JITPRD> alter database switchover to JITSDB verify; alter database switchover to JITSDB verify * ERROR at line 1: ORA-16475: succeeded with warnings, check alert log for more details The default name of the callout configuration file is The connect descriptor can be configured in one of two ways: Oracle Database PL/SQL Language Reference for more information about the DB_ROLE_CHANGE system event. If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. Create a trigger on this event to perform actions specific to your environment after a switchover or failover, such as updating the name resolution service to point to the new primary. The other configurations that are not required but they might make your fast-start failover go smoothly. Event notification and database connection failover support is available to database clients connected to local database services when a broker-managed failover occurs. To stop the observer when fast-start failover is enabled, the primary database and target standby database must be connected and communicating with each other. The broker initiates a failover after the number of seconds specified by this Nothing will ruin your day faster than finding out that the standby the observer just failed over to is 12 hours behind in applying redo. If the standby database is not enabled for management by the broker, then the failover cannot occur. How to Implement Fast-Start Failover 11g - Ed Chen Logic In such cases, the failed primary database is reinstated as a physical standby database. Restarts the new standby (former primary) database if the switchover occurs to a physical standby database, and Redo Apply begins applying redo data from the new primary database. callout directory. add service command. DGMGRL to manage multiple observers on multiple configurations. Synopsis. You can also specify a list of ORA- errors that will initiate FSFO failover. A failover may or may not result in data loss depending on the protection mode in effect at the time of the failover. The advanced way is in the following article: Connect-Time Failover by a Dynamic Service Name. On primary database NORTH, execute the following: On standby database SOUTH, execute the following: Services that are to be active while the database is in the physical standby role must also be created and started on the current primary database regardless of whether the service will be started on that database or not. FastStartFailoverLagLimit configuration property. environment that is guaranteed to either lose no data (when the There are configuration requirements that must be met in order to publish and properly handle FAN events generated as the result of a broker-managed failover. This section describes how to configure and verify each prerequisite. only. If there is another standby database that is available for failover, you can perform a manual failover to that standby database after you first disable fast-start failover using the FORCE option on that standby database. Then, on the Fast-Start Failover Configure page, select the standby database that should be the target of a failover. When you execute commands that affect multiple observers, if you have not specified a name and location for the observer configuration file, then broker searches the current working directory for a file named observer.ora. Broker Configuration Has Multiple Registered Observers. You must use the Oracle wallet to store the credentials for all broker configurations to be managed. After a failover, the broker publishes Fast Application Notification (FAN) events. You cannot perform a switchover to a snapshot standby database unless you first convert it back to a physical standby database. Switchover to a logical standby database is disallowed when the configuration is operating in maximum protection mode. Attempt to open the primary database, or the following error may be returned: This error may return if the fast-start failover validity check fails or does not complete in under two minutes. Some properties have changed between those releases. As a result the observer may still initiate fast-start failover to the target standby database, if conditions warrant a failover. PRIM> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN; For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. For instance, you could log into the system running observer1 to stop observer2. PDF Oracle Database 19c: Data Guard Administration Workshop Flashing back a database occurs in two stages: For FSFO environments, set db_flashback_retention_target = 60 or higher to provide sufficient Flashback Database history for automatic standby reinstatement. The default name for Starting Observers as Background Processes. Immediate: No additional data is applied on the standby database, resulting in a data-loss . Oracle 12c-Step by Step Manual Data Guard Failover SQL>select sequence#, applied from v$archived_log; Fast-start failover allows the broker to automatically fail over to a previously chosen standby database in the event of loss of the primary database. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . This file If an application has called this function and it has received a status of SUCCESS, then the master observer attempts a fast-start failover.