Monitor the environment to ensure the primary database is available. In this case fast-start failover cannot occur because the databases are not ready to failover. Application Continuity is an Oracle Database feature that enables rapid and nondisruptive replays of requests against the database after a recoverable error that made the database session unavailable. the primary database and the target standby database do not have a network Steps that require the primary to be in a mounted (not open) state are grouped together in the section below entitled Steps Requiring a Bounce of the Primary. To avoid problems due to timing variations, values less than 60 minutes are not recommended and values of 30 or less virtually guarantee Flashback Database failure. The ObserverPingInterval Note that primary and standby databases must be licensed for Oracle RAC or Oracle Active Data Guard in order to use Application Continuity. This can be avoided by first disabling fast-start failover with the FORCE option on the target standby. After a failover, the original primary database can no longer participate in the Data Guard configuration. DG_BROKER_START is set to TRUE and DG_BROKER_CONFIG_FILEn are set correctly SQL> sho parameter broker You can disable fast-start failover if necessary, by using the FORCE option. FAN events are always published through ONS. In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). You must determine which available standby databases should be targets for failover. When DGMGRL starts, if the DG_ADMIN Do this prior to every failover test. If the failover fails for any reason, it could leave the target standby database inoperable, regardless of whether the target standby database is ready to failover. If you already have an FRA, you may need to increase its size in order to accommodate the Flashback Database files. the observer was killed after the stall began, but before the failover timeout had elapsed). 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. Therefore, the target standby never falls behind the primary However the target can receive redo from a far sync instance.). The mode can have one of the following values: DISABLED: Fast-start failover is disabled. disable fast-start failover with the FORCE option on the SQL> startup ORACLE instance started. This list describes restrictions when fast-start failover is enabled. As a result the observer may still initiate fast-start failover to the target standby database, if conditions warrant a failover. Data guard Configuration details:- Login in to Standby Server:- Step:1 Check the database role and open_mode Select name,open_mode,database_role from v$database; Starting Multiple Observers On a Single Host. irrespective of its content, indicates that the script executed successfully. Unless action is taken to change the failover target to one of the bystanders, the new primary will be without a failover target until the former primary is reinstated as a standby. SET ObserverConfigFile used to specify a customized observer configuration file. A good method to determine Flashback Database storage requirements is to enable Flashback Database and observe the amount of storage it uses during several peak loads. The broker may not be able to disable fast-start failover on all databases in the broker configuration when you issue the DISABLE FAST_START FAILOVER FORCE command. file (fsfo.dat). For this build, we will use a single physical standby database. After the patch has been successfully applied to all databases, take the following steps to enable fast-start failover and start the observer. database is in the primary role. FSFO configurations in Maximum Performance mode may limit potential data loss by specifying the maximum allowable age of transactions that are lost during a failover. fsfocallout.ora. However, there may be situations in which you must disable fast-start failover when In such cases, the failed primary database is reinstated as a physical standby database. All other registered observers are considered to be backup observers. In fact, failovers are so reliable, fast, and simple that switchovers become the exception rather than the rule. The Oracle Database 11g observer can make use of specific credentials, allowing the same wallet to be used for multiple observers with different SYS passwords. Configure one or more active standby databases Minimize downtime for upgrades Because fast-start failover was not disabled on the target standby database, the observer may still attempt a fast-start failover to the target standby database should conditions warrant a failover. For example: Fast-start failover occurs if both the observer and the target standby database lose connection to the primary database for the period of time specified by the FastStartFailoverThreshold configuration property. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: 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. If the value is non-zero, failover is possible any time the standby database's apply The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. It's generally a good idea to store the state file in a directory associated with the database to avoid locking issues when running multiple observers on the same host. For instance, you could log into the system running observer1 to stop observer2. You can use the broker's reinstate capability to make a failed primary database a viable standby database for the new primary. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. configuration. Cancel MRP process. Stopping a Specific Observer When There are Multiple Observers. 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. During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. This is typically done for planned maintenance of the primary system. DGMGRL> show configuration Configuration - CDB01_fraad1_CDB01_fraad3 Protection Mode: MaxAvailability Members: CDB01_fraad1 - Primary database CDB01_fraad3 - (*) Physical standby database These commands can be issued from the DGMGRL command line, but it is not necessary to log on prior to using them. When performing a failover in a configuration whose standbys are all of the same type, choose the standby database that has the smallest transport lag. When performing a switchover in a configuration whose standby databases are To enable fast-start failover with DGMGRL, issue the ENABLE FAST_START FAILOVER command while connected to any database in the broker configuration, including on the observer computer. Notice that the terminal session appears to hang after starting the observer. The observer is the key element that separates Data Guard failover from its pre-FSFO role as the plan of last resort to its leading role in a robust high availability solution. You must The remaining Data Guard-related parameters will be set by Broker later in the walkthrough. If the WAIT option is included in the The old Primary must have been running in flashback mode before the failover. Oracle Database 10g allows a different password file to be used as long as the SYS passwords are the same on the primary and standby. broker does not allow the primary database to commit transactions until it has regained The existence of a .suc file, These clients can be configured for Fast Connection Failover (FCF) to automatically connect to a new primary database after a failover. Another consequence of immediate failover is that all other databases in the configuration are disabled and must be reinstated or re-created before they can serve as standby databases for the new primary database. connection, or the database on which you issued the disable fast-start failover Add the wallet location and override to sqlnet.ora. You can also reinstate bystander standby databases that were disabled during a failover operation. Disabling Fast-Start Failover Using DGMGRL. Write Engineering Change Proposal documentation and reports to request permission to install, replace . 3. environment variable is set and the specified directory has the If the target is a snapshot standby database, the broker first converts the database to a physical standby database. See Troubleshooting Problems During a Switchover Operation for more information. guaranteed to lose no data. See Reenabling Disabled Databases After a Role Change. Complete Failovers in Configurations Using Far Sync Instances. It is actually a low-footprint OCI client built into the DGMGRL CLI (Data Guard Broker Command Line Interface) and, like any other client, may be run on a different hardware platform than the database servers. Before enabling fast-start failover, use one of the following techniques The connect descriptor must contain the SERVICE_NAME parameter in either case. All standbys other than the failover target are considered bystanders (v$database.fs_failover_status = 'BYSTANDER'). Automatic failover quickly and reliably fails over the standby Autonomous database to the primary database role, without requiring you to perform any manual steps. Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. Do not use Shared Server (formerly MTS) for Data Guard. time specified in the WAIT option. For example: Ordinarily the observer connects once to the primary and does not attempt to reconnect unless the connection has failed. To prevent automatic reinstatement of the former primary database in these cases, set this configuration property to FALSE. If the FastStartFailoverPmyShutdown configuration property is set to TRUE, the primary database will shut down after FastStartFailoverThreshold seconds has elapsed if redo generation has been stalled and the primary database is unable to reestablish connectivity with either the observer or target standby database. The default value is ALL. This property specifies the amount of data, in seconds, that the target standby database can lag behind the primary database in terms of redo applied. Starting the Observer as a Background Process Using Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs $DG_ADMIN directory. Alternatively, if you intend to switch back to the original primary relatively soon, then you may re-enable the disabled standby databases after the switch back. alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. A broker configuration can belong to multiple groups. However, fast-start failover cannot occur when the target standby database is in an unobserved state. the primary role, use the PreferredObserverHosts Other members of the configuration will receive redo from the designated redo source based on the new primary. During an immediate failover, the broker performs the failover steps described in How the Broker Performs an Immediate Failover Operation. Only the observer can initiate FSFO failover. For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. Learn how to use Oracle Data Guard broker to manage databases during switchover and failover. The default A switchover is a role reversal between the primary database and one of its standby databases. See Disabling Fast-Start Failover. The subcommands for this verb include start, stop, setMaster, show, and delete_alternate_observer. Sets up redo transport from the new primary to the other members of the configuration, Starts Redo Apply services on the new standby, Ensures the other standbys in the broker configuration are viable to the new primary, Integrates with Oracle Clusterware and Oracle Global Data Services (GDS) to ensure that the proper services are started after a role change. This specifies how often the observer establishes a new connection to the primary database. Only two databases, the primary and the failover target, can be in the FSFO configuration at any given time. Other logical standby bystander databases in the broker configuration will remain viable after the switchover. Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database.
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