Tailing the alert logs on the primary and standby is a good way to watch Broker in action and get familiar with how it performs various tasks. If there is only one registered observer, then it works in the same manner that a single observer worked prior to the advent of multiple observers in Oracle Database 12c Release 2 (12.2.0.1). The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. This is to ensure that the service definition gets propagated to the physical standby database via the redo stream and thus allows for the service to be started on the physical standby database. If the target standby database is ready for failover, then the master observer immediately directs the target standby database to fail over to the primary database role. By default, the observer will initiate failover to the target standby if and only if ALL of the following are true: Oracle Database 11g Rel 1 introduced user configurable failover conditions that can trigger the observer to initiate failover immediately. configuration named ConfigurationSimpleName. If this occurs, run 'stop observer' and try again. The master observer uses the value specified by either the DGConnectIdentifier or ObserverConnectIdentifier database properties to connect to the primary and fast-start failover target standby databases. This includes the following: broker configuration is in UNSYNC or LAGGING state or unobserved state, failover target is invalid, reinstatement is in progress, or a master observer switch is in progress. A complete failover is the recommended and default failover option. 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. See Reenabling Disabled Databases After a Role Change for more information. If there is only one standby database in the configuration, you can skip this step and continue with Task 3. The observer configuration file is a text file and the syntax to define observers and groups is similar to that used in the listener.ora or tnsnames.ora files. The list is empty by default. Initiate the failover on the standby database STAN: If the target is a snapshot standby database, the broker first converts the database to a physical standby database. The master observer never waits for the threshold to expire to perform a fast-start failover in the following situations: If the master observer determines that any of the user-configurable conditions has been detected, then it attempts a fast-start failover. A far sync instance or Zero Data Loss Recovery Appliance is not a database and therefore cannot be the target of a role transition. When you are experiencing network disconnections and you issue the DISABLE FAST_START FAILOVER FORCE command on the primary database or a standby database that does not have connectivity with the primary database, fast-start failover may not be disabled for all databases in the broker configuration. It could optionally also be removed from the primary database if there is no intention to ever run this service on the current primary database. ConfigurationSimpleName. For more details about managing redo transport services using database properties, see Managing Redo Transport Services. 3. failover with the FORCE option on the primary database. The commands that can be executed for a group of configurations (as declared in an observer configuration file) are as follows. Verifies that the target standby database is enabled. This support note is available at http://support.oracle.com. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by 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. If necessary, you can shut down the primary or target standby database in a fast-start failover environment. How to switch roles in Oracle Data Guard - The Geek Diary the primary and target standby databases. Flashback Database stores its logs in the Flash Recovery Area (FRA), so the FRA must be large enough to store at least 60 minutes of Flashback Database history. Note that these properties only affect whether primary shutdown and automatic reinstatement are performed if a fast-start failover occurs because the primary crashed or was isolated from the observer and target standby database. If only a file name is the current working directory. If the value is non-zero, failover is possible any time the standby database's apply ORACLE instance shut down. To proceed, you must first disable fast-start failover using the FORCE option, and then perform a manual failover. Use Broker's "show configuration" command to determine FSFO status and the "show database statusreport" command to drill down for details if Broker reports a problem. Without the credentials, Broker will complete the role transition, but will leave the databases in need of a manual restart. These are some points to consider before you begin a switchover. It's good practice to use separate listeners for application connections and Data Guard connections. When restarting the databases, you may restart them in any order. created when the START OBSERVER command is issued. Broker keeps its configuration details in flat file. This prevents a "split brain" condition if a failover occurs since none of the changes made to the isolated primary can be made permanent. A fast-start failover to the target standby database fails. It is very much useful, when the organization has multiple standby sites. Installing and starting an observer is an integral part of using fast-start failover and is described in detail in the following sections: Oracle Data Guard Installation explains that you can either install only the Oracle Client Administrator or you can install the complete Oracle Database Enterprise Edition or Personal Edition on the observer system. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. All Data Guard environments should enable force logging at the database level in order to guard against nologging tablespaces from being added. Use synonyms for the keyword you typed, for example, try "application" instead of "software.". Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. In such cases, the failed primary database is reinstated as a physical standby database. If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. Note: if the observer loses contact with the primary, but the standby does not, the observer can determine that the primary is still up via the standby. from another DGMGRL session. Be aware that if you issue the following manual commands on either of those databases, then both the SALESRO and SALESRW services would be started on the databases regardless of what you may have earlier specified with the SRVCTL -role qualifier. An observer is an OCI Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. In a DataGuard environment when the Primary instance fails you need to go through the Failover and Reinstate processes in order to restore the database service, as described in the documentation: Changes a standby database to the primary role in response to a primary database failure. If both of those observers are unavailable, the observers the service configuration. If this In this case, only observers on ob1-host and [PATCH v5 0/6] Add Toshiba Visconti Video Input Interface driver 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. Oracle Data Guard can switch a standby database to the primary role in case a production database becomes unavailable due to . directory does not have the required permissions. You can upgrade the protection mode later, if necessary, as described in Setting the Protection Mode for Your Configuration. The reduced need for manual intervention can increase availability without increasing management costs. configuration file, such as START OBSERVING, After the patch has been successfully applied to all databases, take the following steps to enable fast-start failover and start the observer. If a non-zero value is specified for the A fast-start failover occurred because a user-configurable condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. Currently, this state can be detected only when the database is open. So if the original Primary database is still accessible, you should always consider a switchover first. You will have to reinstate or re-create (see Reenabling Disabled Databases After a Role Change) the standby databases after failover has completed. You cannot perform a manual failover to the target standby database for the same reason. The first step in reinstatement is to flash the database back to the SCN where the standby became the primary (v$database.standby_became_primary_scn on the new primary). The default value is 30 seconds and the lowest possible value is 5 seconds. Oracle also provides Fast Application Notification (FAN) for OCI clients and Fast Connect Failover for JDBC clients. STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. How to Implement Fast-Start Failover 11g - Ed Chen Logic Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. You can query the V$DATABASE view to verify that the observer is started and the configuration is ready for fast-start failover. if the observer is not running, The master observer and the target standby database are inconsistent with regard to the current state of the broker configuration, If the protection mode is maximum availability or maximum protection and the target standby database was not synchronized with the primary database at the time the primary database failed, If the protection mode is maximum performance and the apply point of the target standby database lags the redo generation point of the primary database by more than the amount specified by the FastStartFailoverLagLimit configuration property at the time the primary database failed. Whether or not standby databases that were not the target of failover (bystander standby databases) are disabled depends upon how much redo data they have applied relative to the failover target and the standby type of the failover target: If the failover target is a physical or snapshot standby database, the original primary database must be reinstated or re-created in order to be a standby database for the new primary database. data (in seconds) specified by the value is 10. To stop it, you can do either of the following: Choose the Stop Observer option on the first page of the fast-start failover wizard and click Continue at the bottom of the page. client-side broker files, the specified values are used. Such preparation includes: Ensuring that standby redo log files are configured on the primary database. Reinstatement restores high availability to the broker configuration so that, in the event of a failure of the new primary database, another fast-start failover can occur. crash, data in this file can be used to restart the observer to the The default name of the callout configuration file is 8.2 Private Cloud Appliance and . Each database in a Data Guard configuration must have a unique name. FB Page:https://www.facebook.com/dbahariprasath/? DG_BROKER_START is set to TRUE and DG_BROKER_CONFIG_FILEn are set correctly SQL> sho parameter broker