To configure fast-start failover in observe-only mode: Fast-start failover will not be triggered if the primary or standby database is shut down normally. Configure one or more active standby databases Minimize downtime for upgrades Credentials Required for Access to Broker Configurations. [PATCH v5 0/6] Add Toshiba Visconti Video Input Interface driver To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. This function can be called from a connection to either the primary or any standby in the configuration. 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. Regardless of the method you choose, the broker coordinates the role transition on all databases in the configuration. 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. SUSPENDED is cleared when connectivity with the primary database is restored. alter database recover managed standby database finish; alter database activate standby database; Managed recovery process has been stopped between primary and standby database and standby becomes primary database. After a failover, a bystander will not automatically become the new failover target. flashback logs on that database. Immediate Failovers in Configurations Using Far Sync Instances. prolonged stall, either the observer or target standby database are configured correctly. ZERO DATA LOSS: Fast-start failover is enabled with zero data loss. Automatic failover is optional and can be enabled or disabled on your Autonomous Container Databases with Autonomous Data Guard. command on the observer computer: The observer is a continuously executing process that is Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. The default value is 30 seconds. The name of the callout configuration scripts is specified in Oracle 19c-Step by Step Manual Data Guard Failover Disabling fast-start failover does not stop the observer. If any errors occur during either conversion, the broker stops the switchover. Among many benefits of using this utility, I highlight that while using it, it will not need manual intervention to recover the databases or eventually a switchover in case the primary database becomes unavailable. This feature enables RMAN to duplicate an existing database over the network without requiring a backup to disk or tape. Oracle Database 11g FSFO adds support for Maximum Performance mode (async redo transfer), providing the flexibility to trade durability for performance. lag is less than or equal to the value specified by the specified by the ObserverPingInterval property. distance. An observer is a separate OCI client-side component that run on a different computer from the primary and standby databases and monitors the availability of the primary database. See Directing a Fast-Start Failover From an Application). 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. The ObserverOverride configuration property, when set to TRUE, allows an automatic failover to occur when the observer has lost connectivity to the primary, even if the standby has a healthy connection to the primary. Displays if the standby database's redo applied point lags the primary database's redo generation point by more than the number of seconds specified by the FastStartFailoverLagLimit configuration property and the configuration is operating in maximum performance mode. (See Disabling Fast-Start Failover for important considerations when using the FORCE option.). Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. Instead, when broker notifies the Oracle It is then configured to be active in the PHYSICAL_STANDBY role on the physical standby database SOUTH. Complete Failovers in Configurations Using Cascaded Standbys. PDF Oracle Database 19c: Data Guard Administration Workshop The database cannot provide fast-start failover status information. fast-start failover through Cloud Control. environment variable must have exclusive permissions wherein it can be accessed only Data Guard Failover Options - dba-oracle.com Be sure to include the Data Guard listener in the local_listeners database parameter. As a result, there is no guarantee that the observer will not perform a fast-start failover to the target standby database if the observer determines that conditions warrant a failover. Now let's test switchover in the other direction. Perform SWITCH LOGFILE if necessary. If a non-zero value is specified for the ASYNC. How to Failover to a Standby Database Manually and Rebuild Data Guard Flashback Database records the before-image of changed blocks. 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. Databases that have been disabled after a role transition are not removed from the broker configuration, but they are no longer managed by the broker. Switchover and Failover with DataGuard Broker on Oracle 19c - Data Alchemy The examples shown in this section do not necessarily show the specific attributes you might need to use in your own environment. How to Enable Fast-Start Failover in Oracle Data Guard The existence of a .suc file, 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. 3. After step 3 completes, you can open the new Primary database STAN: Create a unique connect alias for each database. The example uses the FROM ACTIVE DATABASE clause introduced in 11g that allows RMAN to create a standby database by copying the primary across the network without the need to store the backup files on disk or tape. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). Oracle Real Application Clusters Administration and Deployment Guide for information about Application Continuity, The broker simplifies switchovers and failovers by allowing you to invoke them using a single key click in Oracle Enterprise Manager Cloud Control (Cloud Control) or a single command in the DGMGRL command-line interface (referred to in this documentation as, Ensure that the standby database you choose to be the target of fast-start failover has its, Oracle Data Guard Concepts and Administration. by the current operating system user who is running DGMGRL The subdirectories Reenabling Disabled Databases After a Role Change describes how to restore their viability as standby databases. The service can be started on the physical standby only after the redo generated by starting the service has been applied. The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. Follow the guidelines described in Choosing a Target Standby Database. But it will also continue trying to reconnect to the primary database indefinitely. If you re-create the old primary database, it must be created as the standby type of the old standby database. fsfocallout.ora and they have the required permissions. You must set both irrespective of its content, indicates that the script executed successfully. If there are multiple observers, then only one of them is the master observer. See Oracle Data Guard Concepts and Administration for information about tuning the log apply rate for a physical standby database. The lowest possible value is 5 seconds. Change Standby to Primary Database. When DGMGRL starts, if the DG_ADMIN If the observer is unable to regain a connection to the primary database within the specified time, and the target standby database is ready for fast-start failover, then fast-start failover ensues. occur. create the directory specified by the DG_ADMIN environment variable and Complete Failovers in Configurations Using Far Sync Instances. This feature increases the availability of your database in the event of a disaster by reducing the need for you to perform a failover operation manually. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. Enabling fast-start failover in a configuration operating in maximum performance mode provides better overall performance on the primary database because redo data is sent asynchronously to the target standby database. In a manual failover, you convert a standby database to a primary database because the original primary database failed and there is no possibility of recovering the primary database in a timely manner. Here's a one-liner observer startup for *nix. We will create 4 SRLs starting with group# 11. The connect descriptor must contain the SERVICE_NAME parameter in either case. Once an observer is started, no further user interaction is required. For reliable startup, the initial connection should always be made to the primary. 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. The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database. (If there are other conditions, unique to an application, that would warrant a fast-start failover then the application can be set up to call the DBMS_DG.INITIATE_FS_FAILOVER function and start a fast-start failover immediately should any of those conditions occur. there is a lost network connection, be aware that the observer may attempt a All database connections associated with the observer, including the initial connection, must use dedicated server connections. How To Configure Client Failover For Data Guard Connections - Oracle Immediate Failovers in Configurations Using Cascaded Standbys. If the protection mode was at maximum protection, it is reset to maximum performance. For example: In the following example, assume the network between the primary database and the observer has failed. The ObserverPingInterval Group definition this section is optional. A database in the primary role will not open until it has verified with the observer that it is still the primary. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. FSFO builds upon a number of other Oracle technologies and features such as Data Guard, Flashback Database, and Data Guard Broker. callout directory. A switchover guarantees no data loss. These requirements are supplemental to those described in the documents previously referenced and in the following client-specific guides: Oracle Data Provider for .NET Developer's Guide for Microsoft Windows. When running the START To switchover to a standby that is not the current failover target: John Smiley [jrsmiley@gmail.com] is a persistent storage architect for a major online retailer. The redo transport mode used to send redo to the target standby database or the database currently in the primary role. The walkthrough begins with a single database that will become the primary of a Data Guard configuration. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. Disabling Fast-Start Failover Using DGMGRL. In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). It automatically recovers the maximum amount of redo data for the protection mode the configuration is operating in. PRIM>STARTUP MOUNT; 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. You can create two callout configuration scripts, a There is little risk in enabling Flashback Database to determine its storage requirements - it can be disabled while the primary is open if necessary. A value of TRUE helps to ensure that an isolated primary database cannot satisfy user queries. command START OBSERVER IN BACKGROUND. Reinstate the former primary database as a new standby database. 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. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. If you performed a failover or switchover that requires you to re-create the failed primary database or standby databases that were disabled during the role transition, then follow the procedures in the Oracle Data Guard Concepts and Administration chapter, "Creating a Physical Standby Database" and also the Oracle Data Guard Concepts and Administration chapter, "Creating a Logical Standby Database.". mode when the fast-start failover target is a logical or physical standby database that By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. If the standby database's redo applied point is within that many seconds of the primary database's redo generation point, a fast-start failover will be allowed. The information in this guide is based on practical experience gained from deploying FSFO in a global corporate production environment. Once the observer has initiated a fast-start failover, the primary database shuts down automatically. Make sure that your OS environment on the standby is setup. Monitor the environment to ensure the primary database is available. STOP OBSERVING, and SET Note that if failover was performed on a snapshot standby database, the old primary must be either reinstated or re-created as a physical standby database. 2. Switches roles between the primary and standby databases. The application needs to catch this error and respond accordingly. Connect-Time Failover to Standby Database - Ed Chen Logic This is cleared on both when the reinstatement has been completed. Required fields are marked *. Standby databases not involved in the switchover (known as bystander standby databases) continue operating in the state they were in before the switchover occurred and will automatically begin applying redo data received from the new primary database. This may take a few minutes. Administration at the target standby site should be as comprehensive as that at the primary site because the standby database may assume the primary role without prior notice. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. Valid values are >= 100. Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_DG package. In order to accommodate all load conditions, Oracle recommends having at least one more SRL group than the number of ORL groups of the same size. guaranteed to lose no data. Notice that the former primary is now disabled. If there is more than one registered observer, then this command returns an error; a name is required if there is more than one observer. SET MASTEROBSERVER TO allows you to manually change the observer configuration file. SHOW OBSERVER command to confirm that the switch took place. In a Data Guard environment primary database is open in read write mode and the standby database in read only mode for reporting purpose. become the master observer. To protect the files, it's good practice to store them in separate filesystems. The broker continuously monitors for all sessions that are connected 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. Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. If the Add the wallet location and override to sqlnet.ora. environment variable is set and the specified directory has the After the conversion, the broker will start Redo Apply to apply accumulated redo data, before failing the database over to the primary role. Note that role changes to logical standby databases always result in physical standby database bystanders being disabled. times that the observer retries a failed ping before it initiates a Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. All other registered observers are considered to be backup observers. See the "DISABLE FAST_START FAILOVER" command in Oracle Data Guard Command-Line Interface Reference for more information. If both the observer and designated standby database lose connectivity with the primary database for longer than the number of seconds specified by the FastStartFailoverThreshold configuration property, the observer will initiate a fast-start failover to the standby database. This property also affects whether the broker skips viability checks of bystander standby databases when a fast-start failover occurs. It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. You can use the broker's reinstate capability to make a failed primary database a viable standby database for the new primary. To issue commands and interact with the Create a trigger based on the, Oracle Database PL/SQL Language Reference, Choosing a Target Standby Database for Switchover, Choosing a Target Standby Database for Failover, Scenario 9: Performing a Switchover Operation, Scenario 10: Performing a Manual Failover Operation, Database Service Configuration Requirements, Troubleshooting Problems During a Switchover Operation, How the Broker Performs a Complete Failover Operation, How the Broker Performs an Immediate Failover Operation, Setting the Protection Mode for Your Configuration, Scenario 7: Enabling Fast-Start Failover When a Far Sync Instance Is In Use, Description of "Figure 6-1 Relationship of Primary and Standby Databases and the Observer", Enabling Fast-Start Failover Task 7: Configure Actions Before and After Fast-start Failover (Optional), Directing a Fast-Start Failover From an Application, Fast-start Failover Callout Configuration Files, Oracle Data Guard Command-Line Interface Reference, Description of "Figure 6-2 The Observer in the Fast-Start Failover Environment", Oracle Enterprise Manager Command Line Interface. Click Disable in the Fast-Start Failover wizard. See Setting the Protection Mode for Your Configuration. REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. This action will result in loss of data and the possibility of two databases in the configuration simultaneously assuming the primary database role. The following paragraphs describe the supported availability modes. expires. See Disabling Fast-Start Failover. Use broker configuration properties to set the time taken to detect a Careful consideration should be given before enabling fast-start failover for either of these conditions because doing so will supersede availability options provided by Oracle Clusterware. If clients are already configured to automatically time out and reconnect if they don't get a response from the database, a simple but effective approach is to use a network alias (e.g. 11.2 rac servicefailover - After a failover, the broker publishes Fast Application Notification (FAN) events. operation can be automated using callout scripts. Commit latency is not affected by redo transfer, but committed transactions whose redo has not been received by the standby will be lost during failover. Broker checks to see if Flashback Database is enabled on the primary and failover targets when FSFO is enabled. the primary database and the target standby database do not have a network Change the failover target to the standby being switched over to, Change the failover target to the desired standby. To disable fast-start failover, use the Fast-Start Failover wizard in Cloud Control or the DGMGRL DISABLE FAST_START FAILOVER [FORCE] command. Table 6-3 FS_FAILOVER_OBSERVER_PRESENT Column of the V$DATABASE View, The master observer is currently connected to the local database, The master observer is not connected to the local database. the observer was killed after the stall began, but before the failover timeout had elapsed). Set the FastStartFailoverThreshold property to specify the number of seconds you want the observer and target standby database to wait (after detecting the primary database is unavailable) before initiating a failover. If the failover target database is an Oracle RAC physical or snapshot standby database, the broker directs Oracle Clusterware to restart all instances that may have been shut down prior to the failover. 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. The drain_timeout is specified in the SRVCTL The real test of the configuration is a successful role transition in both directions with both switchover and FSFO failover. 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. After fast-start failover is enabled and up to four observers are started, one observer is nominated as the master observer that continuously monitors the environment to ensure the primary database is available. Data Guard Broker Failover - DBA Genesis Support Fast-start failover is faster when you take steps to optimize recovery so that the application of redo data to the standby database is kept up to date with the primary database's rate of redo application. See FastStartFailoverTarget for more information about this property. specified, the file is stored in an appropriate directory under the broker's The "Configuring Authentication" chapter of the Oracle Database Security Guide provides detailed instructions for creating a wallet.

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