This method will disable fast-start failover on all databases in the broker configuration. This list contains some recommendations to obtain better performance when using fast-start failover. In the rare event that a switchover operation fails and you are left with no primary database, retry the switchover command. command for more information about starting the If an application has called this function and it has received a status of SUCCESS, then the master observer attempts a fast-start failover. 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. To stop it, you can do either of the following: Choose the Stop Observer option on the first page of the fast-start failover wizard and click Continue at the bottom of the page. Immediately after issuing command in step 2, shut down and restart the former primary instance PRIM: services. 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. 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. For each broker configuration on which one or more Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). FastStart Failover Ensues: Disaster strikes the primary database and its network connections to both the observer and the target standby database are lost. The same process should work for RAC environment as my colleague has . Oracle Dataguard : Switchover VS Failover - LinkedIn You might, for instance, use this to allow the observer to monitor the databases using the same connect identifiers as the client applications. receives redo data from a far sync instance. Commands For Managing Observers on Multiple Configurations. These commands can be issued from the DGMGRL command line, but it is not necessary to log on prior to using them. If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. Set this property for the primary and target standby database if you want the observer to use a different connect identifier than that used to ship redo data (that is, the connect identifier specified by the DGConnectIdentifier property). These Dataguard Switchover Using DGMGRL A switchover is a role reversal between the primary database and one of its standby databases. While not strictly required, creating a wallet provides a secure way to store the credentials needed to automatically connect to the primary when starting the observer. Click Failover. ObserverConfigFile is a DGMGRL session runtime property. guaranteed to lose no data. These are the actions the broker performs after you start a switchover. 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. Database dismounted. Metadata for the fuzzy snapshot is stored in the flashback log itself. Instead, the old primary database must be re-created as a standby from a backup of the new primary using the procedure described in How to Re-create and Reenable a Disabled Database. To protect the files, it's good practice to store them in separate filesystems. If you have not used the SET ObserverConfigFile command after starting the current DGMGRL client, then the result will always be: ObserverConfigFile=observer.ora. Dataguard PDB level failover support for Multitenant Oracle 19c This support note is available at http://support.oracle.com. As shown in the table, fast-start failover can be enabled in maximum availability 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. This property allows you to specify a priority ordered To configure fast-start failover in observe-only mode: Fast-start failover will not be triggered if the primary or standby database is shut down normally. Unlike ORLs, SRLs should be created with only one member per group. Fast-Start Failover in Oracle 11g Data Guard. the names of the scripts created in the previous step. Reinstatement of the failed primary database as a new standby database failed. An immediate failover is the fastest type of failover. Regards, Narottam Tagged: dataguard dba rac Welcome! JAVA applications can use FAN programmatically by using the JDBC FAN application programming interface to subscribe to FAN events and to execute event handling actions upon the receipt of an event. DG Broker_GottdesKrieges-CSDN select name,open_mode,database_role from v$database; Note: This is to ensure that the service definition gets propagated to the physical standby database via the redo stream and thus allows for the service to be started on the physical standby database. In the following example, ObserverReconnect is set to 30 seconds. STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. The VALIDATE FAST_START FAILOVER command parses the callout Your email address will not be published. Subsequent changes to the same block during the same snapshot are not recorded. Flashing back a database occurs in two stages: For FSFO environments, set db_flashback_retention_target = 60 or higher to provide sufficient Flashback Database history for automatic standby reinstatement. This may result in two databases in the configuration simultaneously assuming the primary database role. Have a means of notifying someone if standby apply falls too far behind. Broker checks to see if Flashback Database is enabled on the primary and failover targets when FSFO is enabled. 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). LGWR is unable to write to any member of the log group because on an I/O error. 3. To stop the observer when fast-start failover is disabled, the primary database must be running. 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. Switches roles between the primary and standby databases. The required attributes vary depending on your configuration (including whether your environment is Oracle RAC-based or single-instance). You cannot perform a manual failover to the target standby database for the same reason. 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. This can be done regardless of whether the failover was done to a physical, logical, or snapshot standby database. Now your old standby database is become primary database, it is highly recommended to consider immediate full backup of primary database. In case of worst situation with data guard primary database, or not available for production than we can activated standby database as a primary production database. irrespective of its content, indicates that the script executed successfully. Note that the new primary database does not need to be restarted. The observer's main purpose is to enhance high availability and lights out computing by reducing the human intervention required by the manual failover process that can add minutes or hours to downtime. To verify the readiness of the fast-start failover configuration, issue the DGMGRL SHOW CONFIGURATION VERBOSE command or the SHOW FAST_START FAILOVER command on the primary database. After setting local_listener, register the database with the listener and verify the services have been registered. property. Failing over the database won't do much good if applications and other database clients don't know where the primary went. For more details about managing Redo Apply services using properties, see Managing Log Apply Services. When the observer loses its connection to the primary database for a period of time greater than that specified by the FastStartFailoverThreshold property, it attempts a failover to the standby database. If you performed a failover or switchover that requires you to re-create the failed primary database or standby databases that were disabled during the role transition, then follow the procedures in the Oracle Data Guard Concepts and Administration chapter, "Creating a Physical Standby Database" and also the Oracle Data Guard Concepts and Administration chapter, "Creating a Logical Standby Database.". 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. If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. Add the wallet location and override to sqlnet.ora. Observers should be installed and run on a computer system that is separate from the primary and standby systems. The default value is 30 seconds. Oracle Database PL/SQL Packages and Types Reference, Stop the observer from any computer system in the broker configuration, as described in, Start the observer on the new computer system, as described in Step 8 of, Enable fast-start failover using the DGMGRL, Shut down the primary database and the target standby database using either DGMGRL, Oracle Database Global Data Services Concepts and Administration Guide, Oracle Real Application Clusters Administration and Deployment Guide, Configure the connect descriptor for connect-time failover. When the primary database and the (non-target) standby database regain network connectivity, the broker will propagate its current fast-start failover setting (ENABLED or DISABLED) to the non-target standby. files include the observer configuration file (observer.ora), observer log The walkthrough begins with a single database that will become the primary of a Data Guard configuration. The observer maintains state information in a file. primary database must have network connectivity. If the database is not managed by Oracle Clusterware, time specified in the WAIT option. In addition, the primary database will shut down if it perceives a loss of connectivity for a period longer than FastStartFailoverThreshold seconds, if the FastStartFailoverPmyShutdown configuration property is set to TRUE. If Flashback Database was enabled on the primary database.If not, the whole setup process must be followed, but this time using the original primary server as the standby. db_domain . If the credentials cannot be obtained, then the attempted command fails (but only for the broker configuration whose credentials have not been obtained). Ensure SPFILE is used SQL> sho parameter spfile 2. You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. FastStartFailoverLagLimit configuration property is set to zero) or When fast-start failover is disabled, no observer is called the master observer; all observers have the same functionality. If there are multiple observers, then only one of them is the master observer. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . The rest of this section provides examples of using DGMGRL SHOW commands to display fast-start failover information and includes sections describing the following views: The DGMGRL SHOW FAST-START FAILOVER command displays all the fast-start failover related information. Since the observer is a specialized instance of a dgmgrl session, the observer host should be installed with either the Oracle Client Administrator software or the full Oracle Database software stack. STOP OBSERVING [cfg_group_name] stops LOCAL observers running on this host (where this DGMGRL is running) for all broker configurations in a specified group. In maximum protection mode, an automatic failover is always possible because the To enable fast-start failover with DGMGRL, issue the ENABLE FAST_START FAILOVER command while connected to any database in the broker configuration, including on the observer computer. Note: You can also use TNS aliases defined in the tnsnames.ora file when setting the local_listener parameter. Note that these properties only affect whether primary shutdown and automatic reinstatement are performed if a fast-start failover occurs because the primary crashed or was isolated from the observer and target standby database. For a system to process an instruction involving data access, these are the certain steps involved: Fetch the block of data from the hard disk (secondary/permanent storage) to the primary memory (e.g. Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. Once an observer is started, no further user interaction is required. Post failover, there are two methods of rebuilding your failed primary Method 1: Rebuild from scratch -> RMAN duplicate Method 2: Flashback database -> only if Flashback was enabled Reinstate failed primary: When you use data guard broker, with just one command, the primary can be rebuilt. That process is shown here. After a failover, the broker publishes Fast Application Notification (FAN) events. Make sure everything is working before moving on. In maximum availability mode, the behavior depends on the value of the STANDBY> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. Example 6-2 Sample Observer Configuration File. multi-tenant environments Know the database downgrade steps in case the upgraded database isn't compatible with the environment Discover the features and benefits to the organization when it moves from the old database . Valid values are >= 100. If possible, confirm that fast-start failover has not Disaster Recovery with Oracle Data Guard - online presentation For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. All physical and snapshot standby databases will be disabled and must be re-created from a copy of the new primary database after a switchover to a logical standby database. if the observer is not running, The master observer and the target standby database are inconsistent with regard to the current state of the broker configuration, If the protection mode is maximum availability or maximum protection and the target standby database was not synchronized with the primary database at the time the primary database failed, If the protection mode is maximum performance and the apply point of the target standby database lags the redo generation point of the primary database by more than the amount specified by the FastStartFailoverLagLimit configuration property at the time the primary database failed. To perform specified actions before or after a fast-start failover directory. When enabling fast-start failover, the broker verifies that the property indicates an existing standby. Even if you have successfully connected to a database server in the broker configuration using the CONNECT command, this command ignores the existing connection and uses the credentials stored in Oracle wallet. 2. You must also start and stop the SALESRO service on the primary so that it can be started on the standby. The observer automatically starts the reinstatement process. The primary database can be reinstated if it had flashback database enabled. fsfo_hostname.dat. ORACLE instance shut down. Keep this trigger as simple and reliable as possible, limiting it to only what is absolutely necessary at the moment of role transition, since any failures at this point may affect availability. POTENTIAL DATA LOSS: Fast-start failover is enabled with some data loss. Oracle FAN with Oracle Data Guard but without using Oracle Grid/ RAC Once the observer has initiated a fast-start failover, the primary database shuts down automatically. The following list indicates the extent to which fast-start failover is disabled in the broker configuration when the DISABLE FAST_START FAILOVER FORCE command is issued on the primary database, target standby database, and a standby database that is not the fast-start failover target. Stopping a Specific Observer When There are Multiple Observers. FAN events are always published through ONS. Connect-Time Failover to Standby Database - Ed Chen Logic 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. After the fast-start failover completes successfully, the master observer will attempt to reinstate the former primary database as a new standby database when a connection to the former primary database is reestablished, and the FastStartFailoverAutoReinstate configuration property is set to TRUE. To disable fast-start failover, use the Fast-Start Failover wizard in Cloud Control or the DGMGRL DISABLE FAST_START FAILOVER [FORCE] command. If this is an Oracle RAC physical standby database managed by Oracle Clusterware, then the broker directs Oracle Clusterware to restart the new standby database. In this case, no attempt is made to transmit any unsent redo from the far sync instance to the target physical standby prior to converting the physical standby into a primary database. FSFO configurations in Maximum Performance mode may limit potential data loss by specifying the maximum allowable age of transactions that are lost during a failover. The values that indicate FSFO is ready for failover are listed below. SQL> Select Database_role from v$Database; A trigger on the DB_ROLE_CHANGE system event can be used to update the naming service and, with the proper client cache TTL settings, clients can connect to the new primary very quickly. Services that must be active in any given database role (primary, physical standby, logical standby, or snapshot standby) must be configured with the Server Control utility (SRVCTL) explicitly on each database where the service must be active. There may or may not be data loss depending upon whether your primary and target standby databases were synchronized at the time of the primary database failure. In this example, there are 3 ORLs with a max group# of 3. In this mode, no actual changes are made to your Broker configuration. To allow the master observer to automatically reinstate the former primary database, the database must be started and mounted. Rather, fast-start failover will be enabled in accordance with the current protection mode. When you configure data guard using OCI console, the default mode is set to maxprotection. Note the primary and target standby must have connectivity for this command to complete successfully. It is then started and stopped on the primary database. If reinstatement of a database fails, its status changes to ORA-16795: the standby database needs to be re-created. After a failover, the original primary database can no longer participate in the Data Guard configuration. The broker first converts the original primary database to run in the standby role. Syntax for Mandatory Configuration Declaration. Now it will return PRIMARY. created under this directory by DGMGRL will also have the same permissions. If the DG_ADMIN environment variable is not defined, or the Disabling Fast-Start Failover Using Cloud Control. orapwd file=$ORACLE_HOME/dbs/orapw$ORACLE_SID. At a minimum, you must set db_unique_name. 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. 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. . 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 following conditions apply when multiple observers are registered for one configuration: When fast-start failover is enabled, one of the observers is the master observer. Broker maintains these parameters by issuing ALTER SYSTEM commands as appropriate during role transitions, database startup/shutdown, and other events. Add the SRLs. Once the Oracle instance is transitioned into primary database status in either switchover or failover, the life of the database as the standby ends and its service as the primary database .