In short, the failover is the deformation of the production (primary) database and activating standby database as the primary. Any apply delay must be removed before beginning a switchover. Bystander standby databases that are not disabled by the broker after the switchover will continue operating in the state they were in before the switchover. Issue the DISABLE FAST_START FAILOVER command or the DISABLE FAST_START FAILOVER FORCE command. There is no data loss during a switch-over. SUSPENDED is cleared when connectivity with the primary database is restored. Data Guard Switchover/failover to standby The standby database will be activated to serve as the primary database at some point in its life cycle. 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 . Do not attempt to reinstate the old primary database if an ORA-752 or ORA-600 [3020] error has occurred at the failover target. configuration. the observer on ob2-host to become the master In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. The current primary database must have its LogXptMode property set accordingly and must have standby redo logs configured. See Manual Failover for complete information about manual failovers. You 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. You can also reinstate bystander standby databases that were disabled during a failover operation. If both of those observers are unavailable, the observers 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. directory does not have the required permissions. If it reconnects to the primary database before the standby agrees to fail over, then the master observer will stop attempting to initiate a fast-start failover. In this example, there are 3 ORLs with a max group# of 3. If fast-start failover is already enabled, the Enabling fast-start failover and starting an observer process involves the following tasks. SQL> startup ORACLE instance started. Verifies that the target standby database is enabled. Use the callout configuration file and script The default value is 30 seconds. 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. Oracle Data Guard work on two database roles Primary and Standby. For example: Ordinarily the observer connects once to the primary and does not attempt to reconnect unless the connection has failed. 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. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). See Oracle Data Guard Concepts and Administration for more information on using the ALTER SYSTEM FLUSH REDO statement. Whereas a switchover to a logical standby database will invalidate and disable all of the physical and snapshot standby databases in the configuration. If there are many actions that need to take place, put them in a separate script and use the trigger to run the script in an orphan process or thread independent of the database. Some properties have changed between those releases. Permissions Required by the DG_ADMIN Directory. This action may result in two databases in the configuration simultaneously assuming the primary database role should fast-start failover occur. Add the wallet location and override to sqlnet.ora. 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. contains important information about the observer. Databases that have been disabled after a role transition are not removed from the broker configuration, but they are no longer managed by the broker. 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. Note: Many of the Broker database properties correspond to database spfile parameters. 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. The syntax for the optional definition of a broker configuration group is: The group definition section is optional. Its primary job is to perform a failover when conditions permit it to do so without violating the data durability constraints set by the DBA. OBSERVE-ONLY: Fast-start failover is enabled in observe-only mode. The failed primary database requires reinstatement as a new standby database to the new primary. Once the observer is started, you cannot change the file's name and location. See the START OBSERVER Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database: . Be aware that if you issue the following manual commands on either of those databases, then both the SALESRO and SALESRW services would be started on the databases regardless of what you may have earlier specified with the SRVCTL -role qualifier. It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. the SYSDG or SYSDBA privilege. This exercises the configuration, but triggers failover differently than losing contact with the primary. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. Other logical standby bystander databases in the broker configuration will remain viable after the switchover. In the following example, ObserverReconnect is set to 30 seconds. Note that a switchover operation may be started before the specified wait In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. If necessary, you can shut down the primary or target standby database in a fast-start failover environment. However, there may be exceptions to the recommendation to choose a physical standby database as the target standby database. If the Cloud Control agent is installed on the observer If the primary or target standby databases lose connections to all backup observers, then the broker does not try to nominate a backup observer as the new master observer, and the broker reports that the configuration is not observed. In fact, failovers are so reliable, fast, and simple that switchovers become the exception rather than the rule. Regards, Narottam Tagged: dataguard dba rac Welcome! For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. This FAN events are always published through ONS. The following assumes that the standby host has been setup according to Oracle's recommendations and that the operating system, accounts, security, resource limits, directory structure, etc. 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. PRIM>connect /@PRIM as sysdba There is no impact on your current configuration or on applications. disable fast-start failover with the FORCE option on the Follow Smart way of Technology on WordPress.com. All standbys other than the failover target are considered bystanders (v$database.fs_failover_status = 'BYSTANDER'). For example: In the following example, assume the network between the primary database and the observer has failed. This method will disable fast-start failover on all databases in the broker configuration. You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. To stop an observer currently designated as the master observer, first issue the SET MASTEROBSERVER command to designate a different observer as master observer. The lowest possible value is 5 seconds. Reenabling Disabled Databases After a Role Change describes how to do this. You can manage observers through either the Oracle Data Guard Overview pages in Cloud Control or using DGMGRL commands. Reinstatement will have to be accomplished by other means (manual or scripted Broker commands). observer on ob1-host will be given priority over To stop the observer, see Stopping the Observer. This configuration property causes the former primary database to be automatically reinstated if a fast-start failover was initiated because the primary database was either isolated or had crashed. 1)What are the steps to do Switchover/Failover operation manually in 2-node RAC and 2-node DATAGUARD environment. This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. Disabling fast-start failover with the FORCE option when connected to the target standby database guarantees that fast-start failover will not occur. After FSFO is enabled, Broker will continue to check that Flashback Database is enabled during health checks. WAIT option, broker waits for the amount of If the DG_ADMIN environment variable is not defined, or the You can switch back to the original primary and then either retry the switchover to the original target standby, or choose another standby in the configuration to switch over to. The standby can be physical or logical and there can be multiple standbys, but only one of the standbys can be the failover target at any given time. We could not find a match for your search. Then, Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. the primary and target standby databases. Some of the statistics that can be monitored are as follows: LAST_FAILOVER_TIME that shows the timestamp of last fast-start failover, LAST_FAILOVER_REASON that shows the reason for the last fast-start failover.