You want to prevent fast-start failover from occurring because the primary database will resume service soon. Verify there are no active users connected to the databases. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. Data Guard Failover Options - dba-oracle.com Open another prompt and connect to SQLPLUS: Now that we know switchovers work, it's time to test failovers. A database in the primary role will not open until it has verified with the observer that it is still the primary. After a switchover completes, the broker preserves the overall Oracle Data Guard protection mode as part of the switchover process by keeping the protection mode at the same protection level (maximum protection, maximum availability, or maximum performance) it was at before the switchover. The FastStartFailoverTarget configuration property on the primary unless the new property value contains the current fast-start failover target. The NetTimeout property specifies the number of seconds LGWR will block waiting for acknowledgment from the standby in synchronous mode before considering the connection lost (corresponds to the NET_TIMEOUT option of log_archive_dest_n). Make sure everything is working before moving on. If the switchover transitions a logical standby database to the primary role, then: The original primary database will be switched to a logical standby role. Note the following points about the observe-only mode: The primary database can enter UNSYNC or LAGGING state without an acknowledgement from the observer or target standby. Use the EMCLI verb dg_configure_observers. Alternatively, you can query the V$DATABASE view on the target standby database. Because fast-start failover was not disabled on the target standby database, the observer may still attempt a fast-start failover to the target standby database should conditions warrant a failover. Perform SWITCH LOGFILE if necessary. Switchover and Failover Operations - Oracle Help Center The observer is the third party in an otherwise typical primary/standby Data Guard configuration. In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). about starting the observer as a background not already enabled, the observer waits until fast-start failover create the directory specified by the DG_ADMIN environment variable and present, you must start the observer manually using the following fast-start failover when: A network outage isolates the primary database from the observer and the target standby database before conditions exist that warrant a failover. Once Flashback Database has succeeded, the observer will convert the database to a standby, bounce it, and begin apply services. The time interval starts when the observer first loses its connection to the primary database. The following sections describe how to reinstate or reenable a database. You can also query the V$FS_FAILOVER_STATS view to display statistics about fast-start failover occurring on the system. crash, data in this file can be used to restart the observer to the Both Cloud Control and the DGMGRL CLI will do this automatically as part of failover. If there are physical or snapshot standby databases in the configuration and the switchover occurs to a logical standby database, you need to re-create those databases from a copy of the new primary database and then reenable those databases, as described in Reenabling Disabled Databases After a Role Change. Verifies that the target standby database is enabled. SQL>STARTUP; The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. Oracle Data Guard configuration with DGMGRL. If client-side ONS configuration is used, the client-side ONS configuration file must specify the hostname and port of the ONS daemon(s) of the primary database and each standby database. However, there may be situations in which you must disable fast-start failover when To achieve Note that if the V$DATABASE.FS_FAILOVER_STATUS column has a value of DISABLED, then any values returned for the remaining columns related to fast-start failover (V$DATABASE.FS_FAILOVER_*) become irrelevant. To optimize the log apply rate: Do not configure the DelayMins database property to delay applying archived redo log files to the standby database (see Managing Log Apply Services for more information). Oracle Data Guard work on two database roles Primary and Standby. observer name, host, whether it is the master observer, when it became the master The real test of the configuration is a successful role transition in both directions with both switchover and FSFO failover. FB Page:https://www.facebook.com/dbahariprasath/? Opens the new primary database in read/write mode. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. The guide makes few assumptions about your existing environment and includes examples for creating a physical standby database and Data Guard Broker configuration. 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 primary database can be mounted, it may be possible to flush any unsent redo data from the primary database to the target standby database using the ALTER SYSTEM FLUSH REDO SQL statement. directory does not have the required permissions. So if the original Primary database is still accessible, you should always consider a switchover first. The broker initiates a failover after the number of seconds specified by this Reenabling Disabled Databases After a Role Change describes how to restore their viability as standby databases. In the following example, ObserverReconnect is set to 30 seconds. If you re-create the old primary database, it must be created as the standby type of the old standby database. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). You can start the observer before or after you enable These are the actions the broker performs after you start a switchover. Initiate the switchover on the primary database PRIM: If a fast-start failover was initiated because the primary database had crashed or lost connectivity with the master observer and target standby database, then the master observer automatically attempts to reinstate the former primary database as a standby database, if the FastStartFailoverAutoReinstate configuration property is set to TRUE. observer immediately begins monitoring the status and connections to Complete Failovers in Configurations Using Far Sync Instances. The remaining Data Guard-related parameters will be set by Broker later in the walkthrough. Stopping the observer does not disable fast-start failover. The ObserverPingInterval For each observer, the V$FS_FAILOVER_OBSERVERS view provides the Displays only on a logical standby database that has not yet completed loading a copy of the primary database's data dictionary. Note that enabling FSFO does not make the configuration ready for automatic failover - that requires an observer, which we'll get to next. When fast-start failover is enabled, the primary and standby randomly choose one of the registered observers to be the master. callout directory. The existence of a .suc file, If provided, then each group needs to have at least one broker configuration declared in the second part. This list contains some recommendations to obtain better performance when using fast-start failover. Add the primary database and each standby database to the address list. Add the wallet location and override to sqlnet.ora. Use Recovery Manager (RMAN) to back up the PeopleSoft database on a regular backup schedule. PRIM>STARTUP MOUNT; To stop the observer when fast-start failover is enabled, the primary database and target standby database must be connected and communicating with each other. After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. If the standby database is not enabled for management by the broker, then the failover cannot occur. This results in the observer establishing a new connection to the primary database every 30 seconds. Immediate Failovers in Configurations Using Cascaded Standbys. The group of broker configurations to be managed is declared in the observer configuration file. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. The master observer waits the number of seconds specified by the FastStartFailoverThreshold configuration property before attempting a fast-start failover when the primary database has crashed or has lost connectivity with the observer, as in the following situations: The primary database loses its connections with both the observer and target standby database. The string "NONAME" cannot be used as an observer name. After a failover, a bystander will not automatically become the new failover target. SHOW OBSERVERS [FOR fg_group_name ] shows information about observers for all configurations in the specified group. The default group is all the configurations defined in the observer configuration file. 3. Note that the broker does not use the properties to set up redo transport services and Redo Apply services until you actually switch over the primary database to the standby role. To start an immediate failover, use the DGMGRL FAILOVER TO database-name IMMEDIATE command. To prevent automatic reinstatement of the former primary database in these cases, set this configuration property to FALSE. Once the observer has initiated a fast-start failover, the primary database shuts down automatically. After you need to make the primary database available, first confirm that a See START OBSERVER IN BACKGROUND for more information fast-start failover through Cloud Control. In It may be possible to convert the old Primary into a Standby database now instead of having to do a time consuming duplicate again. This action may result in two databases in the configuration simultaneously assuming the primary database role should fast-start failover occur. Fast-Start Failover in Oracle 11g Data Guard - Database Journal Fast-start failover can be used only in a broker configuration and can be configured only through DGMGRL or Cloud Control. ZERO DATA LOSS: Fast-start failover is enabled with zero data loss. If only a file name is In short, the failover is the deformation of the production (primary) database and activating standby database as the primary.
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