If the primary database does not have connectivity with the target standby database, fast-start failover remains enabled on the target standby database and the observer may still attempt a fast-start failover if conditions warrant a failover. lower detection times for primary database failures. The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. We could not find a match for your search. The reinstated database acts as the fast-start failover target for the new primary database, making a subsequent fast-start failover possible. Note: this state also occurs on the primary during startup when fast-start failover is possible and neither the target standby database nor the observer are present to confirm it is okay to continue opening the database. 4. Worked as a Development and Database Administrator. observers are registered, a directory named If the Cloud Control agent is installed on the observer PRIM>STARTUP MOUNT; A switchover is a role reversal between the primary database and one of its standby databases. ConfigurationSimpleName. This may take a few minutes. WAIT option, broker waits for the amount of observer on ob1-host will be given priority over If the value is non-zero, failover is possible any time the standby database's apply Instead, when broker notifies the Oracle See Oracle Enterprise Manager Command Line Interface. The broker never automatically reinstates the former primary database if a fast-start failover was initiated because a user configuration condition was detected or was requested by an application calling the DBMS_DG.INITIATE_FS_FAILOVER function. You can issue a Testing FSFO failover requires simulating loss of the primary. 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. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. If the protection mode was at maximum availability or maximum performance, it remains unchanged. (Oracle Call Interface) client that connects to the primary and target standby databases Services that must be active in any given database role (primary, physical standby, logical standby, or snapshot standby) must be configured with the Server Control utility (SRVCTL) explicitly on each database where the service must be active. The broker allows the failover to proceed as long as there are no errors for the standby database that you selected to participate in the failover. The behavior of the broker if the master observer fails depends on whether the broker configuration has one observer or multiple observers. Note that the database will not open at this point. Except for testing purposes, it is not recommended that you start more than one observer on the same host for a Data Guard broker configuration. Only two databases, the primary and the failover target, can be in the FSFO configuration at any given time. Is possible if the target standby database displays SYNCHRONIZED and the FS_FAILOVER_OBSERVER_PRESENT column displays YES. 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. November 20, 2009. If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. Note: If you have just enabled archivelog mode, force an archive log creation ( alter system archive log current) to ensure that at least one archive log exists. Switchover/Failover operation in 2-node RAC and 2-node DATAGUARD databases (PDBs) on any of the instances. The new primary database is opened in read/write mode and redo transport services are started. The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. SQL>STARTUP; 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 following sections describe how to reinstate or reenable a database. The syntax for the configuration declaration is: The definition for each broker configuration is: The configuration-name can be different from the name defined in the metadata of the Data Guard Broker configuration. Now it will return PRIMARY. fsfocallout.ora. An application should use caution when calling the DBMS_DG.INITIATE_FS_FAILOVER function because the observer will initiate failover, if at all possible. The broker will not allow a switchover to a standby that has an apply delay configured (DelayMins property is set to a non-zero value). This is The configuration and database status report that the observer is not running and return one of the following status messages: While the configuration is in the unobserved state, fast-start failover cannot happen. In an Oracle Data Guard configuration, the SRVCTL -startoption and -role are updated after switchover to reflect the current open mode and database role on the new primary and standby databases. For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. Some properties have changed between those releases. groups used by multiple configuration commands. These FAN events can be used in the following ways: Applications can use FAN without programmatic changes if they use one of these Oracle integrated database clients: Oracle Database JDBC, Oracle Database Oracle Call Interface (OCI), Oracle Data Provider for .NET ( ODP.NET), or Universal Connection Pool for Java. fast-start failover operation, the observer checks if a fast-start failover miliseconds. To prevent automatic reinstatement of the former primary database in these cases, set this configuration property to FALSE. When running the START If the switchover occurs to a physical standby database, and the former primary 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. In case of primary database failure, you will need to perform failover to transition the standby database to the primary role. For more details about managing redo transport services using database properties, see Managing Redo Transport Services. Connect to the target standby database and issue the FAILOVER command to perform a failover, specifying the name of the standby database that you want to become the primary database: Specify the optional IMMEDIATE clause to perform an immediate failover if any of the following conditions are true: An ORA-752 error has occurred at the standby database, An ORA-600 [3020] error has occurred at the standby database and Oracle support has determined that it was caused by a lost write at the primary database. A failover is a role transition in which one of the standby databases is transitioned to the primary role after the primary database (all instances in the case of an Oracle RAC database) fails or has become unreachable. Flashing back a database is much faster and more seamless (one simple DDL statement) than traditional point-in-time or SCN-based recovery. The minimum value of ObserverPingInterval is 100 This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. After the failover completes, the former primary database is automatically reinstated as a standby database when a connection to it is reestablished, if the FastStartFailoverAutoReinstate configuration property is set to TRUE. 11.2 rac servicefailover - Broker will set the primary to use asynchronous log transport by default. The redo transport mode used to send redo to the target standby database or the database currently in the primary role. These conditions are described in the following table: Dictionary corruption of a critical database. During the failover to the physical standby database, the Oracle 11g DGB performs the following steps: First, it validates that the target standby database is ready to accept the primary role. A failover may or may not result in data loss depending on the protection mode in effect at the time of the failover. the service configuration. In Maximum Availability mode, FSFO guarantees that no transaction that has received a commit acknowledgment will be lost during a failover. Failing over the database won't do much good if applications and other database clients don't know where the primary went. 2. They cannot be reinstated. (For example, if the DBMS_LOGSTDBY.SKIP procedure was used to specify which database operations done on the primary database will not be applied to the logical standby database.). Immediate Failovers in Configurations Using Far Sync Instances. configuration file, such as START OBSERVING, The default name of the observer runtime data file is Although the default value of 30 seconds is typically adequate for detecting outages and failures on most configurations, you can adjust failover sensitivity with this property to decrease the probability of false failovers in a temporarily unstable environment. A switchover to a physical standby database is preferable because all databases in the configuration will be available as standby databases to the new primary database after the switchover operation completes. 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. If the primary is unable to contact the standby after a user specified period of time (NET_TIMEOUT option of log_archive_dest_ n), it drops out of synchronous transfer mode and begins operating as though it were in Maximum Performance mode. Which three are prerequisites for enabling fast-start failover SHOW ObserverConfigFile used to check the runtime property ObserverConfigFile. file, observer runtime data file (fsfo.dat), fast-start failover callout To protect the files, it's good practice to store them in separate filesystems. the current working directory. Performing a Manual Failover Task 1: Determine Which of the Available Standby Databases is the Best Target for the Failover, Performing a Manual Failover Task 2: Start the Failover, Performing a Manual Failover Task 3: Reset the Protection Mode, Performing a Manual Failover Task 4: Re-establish a Disaster-Recovery Configuration. Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. See the Cloud Control online help for more information. Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. FSFO enabled configurations having multiple standbys cannot switchover to a standby that is not the failover target. The observer configuration file is a text file and the syntax to define observers and groups is similar to that used in the listener.ora or tnsnames.ora files. Make sure the last redo data transmitted from the Primary database was applied on the standby database. pre-callout configuration script and post-callout configuration script. Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database. However, if you want the observer to reconnect to the primary database periodically as a means of testing the health of the network connection to the primary, then use the ObserverReconnect configuration property. There is no need to multiplex SRLs in order to protect redo as with ORLs (the redo is already protected in the ORLs of the primary). Data Guard. Startup can fail with "ORA-16647: could not start more than one observer" even when no observer is actually running if the previous observer process terminated without deregistering itself and the new observer isn't using the previous fsfo.dat file. an alias of the broker configuration name. If the primary database is an Oracle Real Application Clusters (Oracle RAC) database, the master observer will attempt to connect to one of the remaining primary instances. directory. In this case, the FS_FAILOVER_STATUS and FS_FAILOVER_OBSERVER_PRESENT columns will appear as shown in the following table and fast-start failover will not occur: Oracle Database Reference for more information about the V$DATABASE view. Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. When you configure data guard using OCI console, the default mode is set to maxprotection. Expected output is shown in blue text. create the directory specified by the DG_ADMIN environment variable and callout directory. (See Disabling Fast-Start Failover for important considerations when using the FORCE option.). Oracle 12c-Step by Step Manual Data Guard Switchover, Manual Upgrading Oracle Database From 11.2.0.4 to 12.2.0.1, Automatically Terminated The Blocking Session By Setting MAX_IDLE_BLOCKER_TIME, Apply Patching On Oracle 21c Database Release Update 21.7.0.0.0, Oracle 21c Point In Time Recovery of Pdb Database, Oracle 21c Cloning a PDB Database Using Sqldeveloper Tool. Issue the following command while connected to any database in the broker configuration, except the database that is to be reinstated: The newly reinstated standby database will begin serving as a standby database to the new primary database. The Column Value in the following table is consistent across instances in an Oracle Real Applications Clusters (Oracle RAC) environment. This directory is created when you run the This file is stored in the It has two parts in the following order: Configuration declaration this section is mandatory. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. Unlike the primary / standby interconnect, where bandwidth and latency are determining performance factors, the observer requires very little network bandwidth and is not overly latency sensitive, allowing the it to be placed practically anywhere a reliable connection is available. To get started, all you'll need is Oracle Database Enterprise Edition Release 10.2 or later, a database, and three hosts: two for the databases and a small host for the FSFO observer. See Setting the Protection Mode for Your Configuration. The target standby database is enabled and is in the APPLY-ON state. physical standby database. If the designated fast-start failover target develops a problem and cannot be the target of a failover, then the broker automatically changes the fast-start failover target to one of the other candidate targets. Check the database role,open_mode in standby server. Oracle Dataguard : Switchover VS Failover - LinkedIn 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. When you select a standby database to be the next primary database after a switchover or a failover, there are several factors to consider. Ensure SPFILE is used SQL> sho parameter spfile 2. Then, on the Fast-Start Failover Change Mode page, click Enabled. There is no data loss during a switch-over. FS_FAILOVER_OBSERVER_HOST shows the name of the computer on which the master observer is running, FS_FAILOVER_OBSERVER_PRESENT shows whether or not the master observer is connected to the local database. Guide to Oracle Data Guard Fast-Start Failover The command fails if the file does not exist. Any unsent redo data residing on the far sync instance is transmitted to the target physical standby prior to converting the physical standby into a primary database. Ensure that the required permissions are granted to the DG_ADMIN Subdirectories within A complete failover is the recommended and default failover option. SWITCHOVER command, and the databases are managed by Oracle Switching over to a logical standby database results in the snapshot and physical standby databases in the broker configuration being disabled by the broker, making these databases no longer viable as standby databases. Whether or not you need the FORCE option depends mostly on if the primary and target standby database have network connectivity: If the primary and target standby database have network connectivity, and the database to which you are connected has network connectivity with the primary database, the FORCE option has no effect. Contains the callout configuration file, pre-callout script, Note that primary and standby databases must be licensed for Oracle RAC or Oracle Active Data Guard in order to use Application Continuity.