See Setting the Protection Mode for Your Configuration. The subcommands for this verb include start, stop, setMaster, show, and delete_alternate_observer. It's good practice to use separate listeners for application connections and Data Guard connections. required permissions, DGMGRL reports an error. If the target is a snapshot standby database, the broker first converts the database back to a physical standby and then starts Redo Apply to apply all the accumulated redo before completing the failover and opening the database as a primary database. Tasks that must be performed before and after a fast-start failover If no value is specified for the required permissions, the admin folder is created Reenabling Disabled Databases After a Role Change describes how to do this. Add the primary database and each standby database to the address list. Start the observer by running dgmgrl and logging in using SYS credentials. This FastStartFailoverThreshold for reference information about the FastStartFailoverThreshold property. The minimum create the directory specified by the DG_ADMIN environment variable and When performing a switchover in a configuration whose standby databases are Just be sure to include a Flashback Database history check in the script to provide an option to abort if a failover would require a manual reinstate. 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. 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. After Example 6-2 Sample Observer Configuration File. Manual failover can be performed even if the pre-condition checks are not met. Once you have completed the switchover back to the original primary, you may then reenable the physical and snapshot standby databases since they are still viable standbys for the original primary database. Step:5Bounce your database and verify database name its open mode and its role. A manual failover is already in progress. By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. observer_hostname.log. FastStartFailoverLagLimit Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by Note that the new primary database does not need to be restarted. Always try to perform a complete failover first unless redo apply has stopped at the failover target due to an ORA-752 or ORA-600 [3020] error. Fast-start failover is enabled, but this standby database is not the target of the fast-start failover. The SHOW CONFIGURATION command will show you which databases can be reinstated and which databases must be re-created. If the value is non-zero, failover is possible any time the standby database's apply See the Oracle Reference and Data Guard Administrator guides for your release for details. If this operation is successful, a zero data loss failover may be possible even if the primary database is not in a zero data loss protection mode. PeopleSoft can be configured for Active Data Guard. Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. 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. You Using Cloud Control, you can view the value of the ApplyLag column for each standby database in the Standby Databases section of the Oracle Data Guard Overview page. Facebook:https://www.facebook.com/HariPrasathdba contains important information about the observer. The primary database can be opened even if there is no acknowledgement from the observer or target standby. Now let's test switchover in the other direction. Initiate the failover on the standby database STAN: SQL>connect /@STAN as sysdba SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; 2. Bystander standby databases can be shut down at any time in any order without impacting fast-start failover. The simple tests described in this guide are fine for making sure the basics are working, but you'll probably want to develop a more comprehensive set of tests suited to your environment and requirements. When a primary loses contact with both the failover target and the observer simultaneously, it enters a "stalled" state (v$database.fs_failover_status = 'STALLED') and any sessions still connected to the primary will block on commit. Each observer has its own log file. This database property is used to specify how the observer should connect to and monitor the primary and standby database. If the database is not enabled, you will not be able to perform a failover to this database. This section lists the steps the master observer takes to determine if a fast-start failover is needed and then to perform one, if necessary. Synopsis. To see the specific parameter, use the "show database StatusReport" command. 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. 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. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . Provides an automatic failover environment The broker selects a target based on the order in which they are specified on the FaststartFailoverTarget property. 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. an alias of the broker configuration name. The broker first converts the original primary database to run in the standby role. The logs also contain other details about the actions that will be performed in case of a failover. If failover occurs to a logical standby database, all physical and snapshot standby databases will be disabled by the broker. failover with the FORCE option on the primary database. There can be up to four Create a trigger on this event to perform actions specific to your environment after a switchover or failover, such as updating the name resolution service to point to the new primary. This is cleared on both when the reinstatement has been completed. 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. The other configurations that are not required but they might make your fast-start failover go smoothly. If fast-start failover is disabled, then manual failover may still be possible. 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. 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. Application Continuity is an Oracle Database feature that enables rapid and nondisruptive replays of requests against the database after a recoverable error that made the database session unavailable. In disaster situations where a failover is necessary, you may be more limited as to which standby database is the best one to pick up the failed primary database's activities. This list contains some recommendations to obtain better performance when using fast-start failover. Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. Observer sites monitor the fast-start failover environment. These clients can be configured for Fast Connection Failover (FCF) to automatically connect to a new primary database after a failover. To specify which observer can be a master observer when a database is in Broker is a Data Guard management utility that maintains state information about a primary and its standby databases. If the DG_ADMIN environment variable is not set, or the When you run commands that need access to the observer After you click the Reinstate button, Cloud Control begins reinstating the database. This can be avoided by first disabling fast-start failover with the FORCE option on the target standby. cannot use a different name for this file. However, you can change the name or the location of the file if you start the observer using the DGMGRL START OBSERVER command and include the FILE IS qualifier. 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. For switchovers, understanding all of the factors can simplify the choice of which standby database to consider as your new primary database. Unlike ORLs, SRLs should be created with only one member per group. The Appendix provides information oncreating a simple wrapper script to start the observer as a background process. The broker selects a target standby based on the order they are specified in the property. must create a .suc and .err file in the Whether or not standby databases that were not the target of failover (bystander standby databases) are disabled depends upon how much redo data they have applied relative to the failover target and the standby type of the failover target: If the failover target is a physical or snapshot standby database, the original primary database must be reinstated or re-created in order to be a standby database for the new primary database. The examples shown in this section do not necessarily show the specific attributes you might need to use in your own environment. primary database. Use the EMCLI verb dg_configure_observers. Verify the configuration from both hosts. See Prerequisites for more information. We can always fail over to it or have it happen automatically if for some reason the primary Managed Instance has [] Do not attempt to reinstate the old primary database if an ORA-752 or ORA-600 [3020] error has occurred at the failover target. The mode can have one of the following values: DISABLED: Fast-start failover is disabled. These conditions are described in the following table: Dictionary corruption of a critical database. Now your old standby database is become primary database, it is highly recommended to consider immediate full backup of primary database. Note: the FSFO observer version must match the database version. 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. Steps that require the primary to be in a mounted (not open) state are grouped together in the section below entitled Steps Requiring a Bounce of the Primary. broker configuration, you must connect through another DGMGRL client Else, broker restarts the new The name of the callout configuration file is fsfocallout.ora. It is also supported for fast-start failover to physical standbys in maximum availability data protection mode.