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Maximum Availability mode uses synchronous redo transfer and FSFO imposes the additional requirement that the redo is recorded in the standby redo log (SRL) of the target standby (AFFIRM option of log_archive_dest_ n). An alternative is to enable flashback database on the primary (and the standby if desired) so in the event of a failover, the primary can be flashed back to the time before the failover and quickly converted to a standby database. Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. connectivity with target standby. Use the EMCLI verb dg_configure_observers. There may or may not be data loss depending upon whether your primary and target standby databases were synchronized at the time of the primary database failure. If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. All Data Guard environments should enable force logging at the database level in order to guard against nologging tablespaces from being added. (as it might in maximum availability and maximum performance modes). switch does not happen until the next time the primary contacts the target standby, Then, on the Fast-Start Failover Configure page, select the standby database that should be the target of a failover. Then, Verify the target standby database is ready for failover. 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. It behaves similarly to START OBSERVING and STOP OBSERVING to operate on all the configurations defined in the observer configuration file. 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. If the primary and target standby databases do not have network connectivity or if the database to which you are connected does not have network connectivity with the primary database, consider using DISABLE FAST_START FAILOVER with the FORCE option. Instead, when broker notifies the Oracle Some properties have changed between those releases. This function can be called from a connection to either the primary or any standby in the configuration. So if the original Primary database is still accessible, you should always consider a switchover first. You can switch back to the original Primary database later by performing another switch over. Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. It also requires Flashback Database to be enabled on both the primary and target standby databases. 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. See theFlashback Database section above for information on storage requirements. STANDBY>ALTER DATABASE OPEN; To install Oracle Data Guard, you need to create two Azure VMs on the same availability set: The primary VM (myVM1) has a running Oracle instance. name of the observer log file is However, if the standby has had contact from the primary within the period of time specified by the FastStartFailoverThreshold property, the standby prevents the failover attempt. fast-start failover through Cloud Control. They must be re-created from a copy of the new primary database. (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.). At a minimum, you must set db_unique_name. It is possible to manually perform an immediate failover to a standby database that receives redo data from a far sync instance. Credentials Required for Access to Broker Configurations. Displays the current fast-start failover mode. This section describes how to configure and verify each prerequisite. When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. They must be re-created from a copy of the new primary database. To reenable broker management of these databases, you must reinstate or re-create the databases using one of the following procedures: If a database can be reinstated, the database will show the following status: Reinstate the database using the DGMGRL REINSTATE DATABASE command or the reinstate option in Cloud Control, as described in How to Reinstate a Database. With increased latency comes decreased throughput; however, in some cases the difference in throughput may be made up by increasing parallelism. The Marketplace image that you use to create the VMs is Oracle:Oracle-Database-Ee:12.1..2:latest. Step:5Bounce your database and verify database name its open mode and its role. Enable Fast-Start Failover Using Cloud Control. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: In this case fast-start failover cannot occur because the databases are not ready to failover. Additionally, the new master observer is identified in the output shown for the SHOW FAST_START FAILOVER and SHOW OBSERVER commands. If the observer is stopped abnormally (for example, by typing CTRL/C), restart it and reference the existing fsfo.dat file with the FILE IS qualifier. Tags: Data Guard, Oracle. 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. It is not reversible. Before a If there is more than one standby database in the configuration, you must explicitly set the FastStartFailoverTarget property on the primary database to name one or more candidate target standby databases. from another DGMGRL session. (See Disabling Fast-Start Failover for important considerations when using the FORCE option.). Another standby database that does not have connectivity with the primary database, fast-start failover is disabled for this database. See the START OBSERVER 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. On the new primary database STAN, perform a SWITCH LOGFILE to start sending redo data to the standby database PRIM. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL. If the switchover occurs to a physical standby database, and the former primary observer as a foreground process. the primary role, use the PreferredObserverHosts 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. If the DG_ADMIN environment variable is not defined, or the The target standby database has contact with the primary database. It is then started and stopped on the primary database. A running observer will follow the primary automatically after a role transition, but a newly (re)started observer won't start if the initial connection is to a down database or one with an out of date or corrupted Broker config file. the primary and target standby databases. For more details about managing Redo Apply services using properties, see Managing Log Apply Services. Broker will validate the configuration, set parameters on both databases, and start managed recovery. 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). Issue the following SRVCTL commands so that both databases in the Data Guard configuration know about the two potential services for each database: To start things up initially, you must manually start the services on the right node. Reconnect within the time specified by the FastStartFailoverThreshold property. Choosing the standby database with the smallest transport lag can minimize the amount of data loss and in some cases, incur no data loss at all. The default value is 30 seconds and the lowest possible value is 5 seconds. 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. services. For any work, queries and help. The observer does not need to coordinate fast-start failover when fast-start failover is disabled, so the primary and target standby do not nominate a master observer until fast-start failover is enabled. Look for the desired data in the RAM. If the If you have not used the SET ObserverConfigFile command after starting the current DGMGRL client, then the result will always be: ObserverConfigFile=observer.ora. Expected output is shown in blue text. Ensure SPFILE is used SQL> sho parameter spfile 2. The information in this guide is based on practical experience gained from deploying FSFO in a global corporate production environment. An spfile is required to persist these changes. Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. change tracking enabled, broker enables block change tracking on the new FastStartFailoverLagLimit configuration property. Bounce your database and verify database name its open mode and its role: SQL> shutdown immediate; ORA-01109: database not open Database dismounted. If the database is managed by Oracle Clusterware, broker does not open any of the However, the event notifying a failover is only published for database services that have been configured to be active while the database is in the primary role on the new primary database. There are many examples, and Ritesh Chhajer offers this example of doing a Data Guard switchover using dgmgrl: 1. lose no more than the amount of data (in seconds) specified by the The selected standby database that will be the fast-start failover target must receive redo directly from the primary database. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. It automatically sets Data Guard related database initialization parameters on instance start and role transitions, starts apply services for standbys, and automates many of the administrative tasks associated with maintaining a Data Guard configuration.