You can specify particular conditions for which a fast-start failover should occur using either Cloud Control or the DGMGRL ENABLE FAST_START FAILOVER CONDITION and DISABLE FAST_START FAILOVER CONDITION commands. If this 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. Download Ebook Oracle 11g 12c Data Guard With Asm Lab Practice A Complete Hands On Lab Practice To Manage A Data Guard . For reliable startup, the initial connection should always be made to the primary. However, there may be exceptions to the recommendation to choose a physical standby database as the target standby database. command does not have a network connection to the primary database. 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. Were sorry. After setting local_listener, register the database with the listener and verify the services have been registered. You can also specify a list of ORA- errors that will initiate FSFO failover. In Oracle RAC configurations, the Inaccessible Logfile and Stuck Archiver health conditions may only be applicable to a single instance. By default, a fast-start failover is done when both the observer and the standby cannot reach the primary after the configured time threshold (FastStartFailoverThreshold) has passed. 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. Stopping the observer does not disable fast-start failover. Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. Setting this property to 'TRUE' (the default) causes the primary to self-terminate. If the DG_ADMIN environment variable is not defined, or the SQL> startup ORACLE instance started. The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. Role Transitions: Switchover and Failover 1 -7 Oracle Data Guard Broker Framework 1 -9 C hoosing an Interface for Administering a Data Guard Configuration 1 -10 Oracle Data Guard: Architecture (Overview) 1 -11 Primary Database Processes 1 -12 . 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. Stopping the Observer When There is Only One Observer. When enabled, re-create the standby database. If the specified log file is not accessible, or the LOGFILE IS option is not used, then the observer output is sent to standard output. How to switch roles in Oracle Data Guard - The Geek Diary On the Data Guard Failover Confirmation page, specify the type of failover that you want to perform: Complete: All available redo is applied on the standby database. Look for the desired data in the RAM. Oracle Dataguard : Switchover VS Failover - LinkedIn The command SHOW OBSERVER provides detailed information about registered observers. alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. create the directory specified by the DG_ADMIN environment variable and In order to fully automate switchover, Broker needs SYSDBA credentials in order to restart one or both databases. On Windows, the directory specified by the DG_ADMIN Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. Now your old standby database is become primary database, it is highly recommended to consider immediate full backup of primary database. Applications can initiate FSFO failover directly using the DBMS_DG.INITIATE_FS_FAILOVER procedure with an optional message text that will be displayed in the observer log and the primary's alert log. See the Oracle Maximum Availability Architecture technical briefs at: When setting the FastStartFailoverLagLimit configuration property, consider these tradeoffs between performance and potential data-loss: A low lag limit will minimize data loss but may impact the performance of the primary database. Errors occurring for any other configuration members will not impede the switchover. Reinstate the former primary database as a new standby database. Your email address will not be published. Data Guard Configuration Details:-. Check the database role,open_mode in standby server. Make sure that xdpyinfo exist under PATH variable. connectivity with target standby. Dataguard PDB level failover support for Multitenant Oracle 19c Note: if the observer loses contact with the primary, but the standby does not, the observer can determine that the primary is still up via the standby. To verify this change, again query the Database_role column of V$DATABASE. FastStart Failover Ensues: Disaster strikes the primary database and its network connections to both the observer and the target standby database are lost. 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. If the database is not managed by Oracle Clusterware, FastStartFailoverLagLimit A failover to a logical standby database requires that all physical and snapshot standby databases be re-created from a copy of the new primary database after the failover completes. You can specify STOP OBSERVER ALL to stop all observers registered in a broker configuration. The foundation of FSFO is Data Guard - a primary and at least one standby. Broker Configuration Has Multiple Registered Observers. 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. Oracle recommends configuring Flashback Database on every database so that if failover occurs to a physical standby database, you can more easily reinstate any disabled standby databases. Other members of the configuration will receive redo from the designated redo source based on the new primary. You can perform a manual failover even if fast-start failover is enabled. database (if real-time query is enabled). 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. FSFO can provide substantial gains in high availability and disaster recovery preparedness for all environments, from inexpensive Cloud-based systems to global distributed data centers. If the protection mode was at maximum protection, it is reset to maximum performance. When you execute commands that affect multiple observers, if you have not specified a name and location for the observer configuration file, then broker searches the current working directory for a file named observer.ora. Failover automation ensures a seamless transition from the primary database to a synchronized standby database in cases of failure, while ensuring database availability by replaying uncommitted in-flight transactions. North_Sales is in the primary role. Oracle 11g Physical standby data Guard Failover steps - Data Guard Part 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. In the media recovery phase, Flashback Database applies redo to bring the database up to the standby_became_primary_scn. SQL> Select Database_role from v$Database; The DB_ROLE_CHANGE event will fire whenever a database is opened for the first time after a role transition. A database in the primary role will not open until it has verified with the observer that it is still the primary. If it detects that Flashback Database was disabled, either manually, or automatically because Flashback Database discovered a problem, Broker signals "ORA-16827: Flashback Database is disabled". If you initiated a complete failover and it fails, you might need to use immediate failover. FastStartFailoverLagLimit configuration property is set to zero) or For more details about managing Redo Apply services using properties, see Managing Log Apply Services. command for more information about starting the on particular instances based on the service configuration. Reinstating the Former Primary Database in the Broker Configuration for more information about reinstatement. To avoid the overhead of recording every change to every block, Flashback Database takes a "fuzzy" snapshot every 30 minutes and only records the before-image block upon its first change since the last snapshot. Performing Database Failover with Oracle 11g Data Guard A switchover is a role reversal between the primary database and one of its standby databases. (Note that the target standby cannot be a far-sync instance. For Oracle Database Release 12.2 and higher, Oracle Enterprise Manager Cloud Control (Cloud Control) supports configuring multiple observers using the Enterprise Manager Command Line Interface (EM CLI). Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. Add the wallet location and override to sqlnet.ora. Regards, Narottam Tagged: dataguard dba rac Welcome! If the configuration is not failable, the DBMS_DG.INITIATE_FS_FAILOVER function returns an ORA error number (it does not signal an exception) informing the caller that a fast-start failover could not be performed. A trigger on the DB_ROLE_CHANGE system event can be used to update the naming service and, with the proper client cache TTL settings, clients can connect to the new primary very quickly. If a single-instance primary database (either Oracle RAC or non-Oracle RAC), or if all instances of an Oracle RAC primary database fail, the observer attempts a fast-start failover. Database dismounted. 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. This not only saves time and minimizes problems by automating an otherwise manual process, it exercises your failover and DR procedures with every flip so that you know the FSFO configuration is sound and, in a real emergency, everyone knows what to do. This feature enables RMAN to duplicate an existing database over the network without requiring a backup to disk or tape. Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. 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. If the database is managed by Oracle Clusterware, broker does not open any of the How we create a failover group in Azure Managed Instance VALIDATE This specifies how often the observer establishes a new connection to the primary database. Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. observer as a foreground process. There is no data loss during a switch-over. The following sections provide information about managing observers: How the Observer Maintains Fast-Start Failover Configuration Information, Patching an Environment When the Observer Is Running and Fast-start Failover Is Enabled.