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Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. If the target is a snapshot standby database, the broker first converts the database to a physical standby database. You can enable fast-start failover from any site while connected to any database in the broker configuration. Startup can fail with "ORA-16647: could not start more than one observer" even when no observer is actually running if the previous observer process terminated without deregistering itself and the new observer isn't using the previous fsfo.dat file. 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. Switchover and Failover Operations - Oracle Help Center Do not use Shared Server (formerly MTS) for Data Guard. expires. This method will disable fast-start failover on all databases in the broker configuration. The subcommands for this verb include start, stop, setMaster, show, and delete_alternate_observer. The current primary database must have its LogXptMode property set accordingly and must have standby redo logs configured. 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. Perform a switchover to a standby database that is not configured as the fast-start failover target, Perform a switchover to the target standby database in a configuration operating in maximum availability mode, unless the standby database is synchronized with the primary database, Perform a switchover to the target standby database in a configuration operating in maximum performance mode, unless the standby database is within the lag limit of the primary database. Use Recovery Manager (RMAN) to back up the PeopleSoft database on a regular backup schedule. For example, if the limit specified is 30 seconds (the default), FSFO guarantees that all transactions that committed prior to 30 seconds ago are preserved during failover. If the standby database is not enabled for management by the broker, then the failover cannot occur. command does not have a network connection to the primary database. 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. In this mode you will need to consider how much data loss is acceptable in terms of seconds and set the FastStartFailoverLagLimit configuration property accordingly. After the database has been re-created, enable broker management of the re-created standby database by using the DGMGRL ENABLE DATABASE command. This may result in data loss. Other members of the configuration will receive redo from the designated redo source based on the new primary. For any work, queries and help. Fast-start failover is inhibited in this case. committing because a fast-start failover may have occurred while it was Broker can be configured to initiate failover on any of the following conditions. The broker interacts with Oracle Clusterware or Oracle Restart to ensure that the appropriate database services are active and that the appropriate FAN events are published after a role change. lose no more than the amount of data (in seconds) specified by the It uses the connect identifier specified in the observer configuration file to locate the credentials for a broker configuration from the Oracle wallet. If possible, confirm that fast-start failover has not This is typically done for planned maintenance of the primary system. db_domain . Observer uses the value of the DGConnectIdentifier property to connect to and monitor the primary and target standby databases. You can, however, perform a manual failover to a snapshot standby. Each group that you define must have at least one broker configuration. Tags: Data Guard, Oracle. How to Re-create and Reenable a Disabled Database. You can also reinstate bystander standby databases that were disabled during a failover operation. By default the file is named fsfo.dat and is created in the working directory where the observer is started. REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. If both HVR and Data Guard were running without latency or if no changes were made to the source database at the time of the failover, it can be assumed that all databases are synced and the no extra steps are necessary; the steps for Graceful Failover can be followed. On Linux/Unix, the directory specified by the DG_ADMIN environment If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. For the RMAN duplicate active database method, the init.ora file (initdb1.ora in the example) requires only one parameter: db_name (it doesn't even have to be the real name of the database - any name will do). The group of broker configurations to be managed is declared in the observer configuration file. Stopping a Specific Observer When There are Multiple Observers. The following sections describe how to perform manual failovers: Reenabling Disabled Databases After a Role Change. Data Guard switchover with dgmgrl - dba-oracle.com You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. These are some points to consider before you begin a switchover. Use broker configuration properties to set the time taken to detect a Then, on the Fast-Start Failover Change Mode page, click Enabled. If the configuration contains physical, snapshot, and logical standby databases, consider choosing a physical standby database as the target standby database. It wouldn't be much of a test if we didn't verify that our durability constraints were being met, so let's make a change on the primary and see if it survives the failover. In maximum protection mode, an automatic failover is always possible because the For example: You can find information about the master observer by querying the V$DATABASE view. present, you must start the observer manually using the following FSFO is a feature of Broker which records information about the failover target, how long to wait after a failure before triggering a failover, and other FSFO specific properties. They can all be done at the same time in a single bounce. Follow the guidelines described in Choosing a Target Standby Database. See Setting the Protection Mode for Your Configuration. Stores files related to the observer and callout configuration. SQL> Select Database_role from v$Database; A switchover to a physical standby database is preferable because all databases in the configuration will be available as standby databases to the new primary database after the switchover operation completes. When DGMGRL starts, if the DG_ADMIN primary database must have network connectivity. ZERO DATA LOSS: Fast-start failover is enabled with zero data loss. A good method to determine Flashback Database storage requirements is to enable Flashback Database and observe the amount of storage it uses during several peak loads. PRIM> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN; 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. If all the databases do not have the same values, SRVCTL attempts to override the values, which will fail on the physical standby database because it is open read-only. Note that the database will not open at this point. If the failover fails for any reason, it could leave the target standby database inoperable, regardless of whether the target standby database is ready to failover. For more details about managing redo transport services using database properties, see Managing Redo Transport Services. 11.2 rac servicefailover 2020-01-28 ORACLE ORACLE RAC/ASM RAC112. When fast-start failover is enabled, the primary and standby randomly choose one of the registered observers to be the master. When you select a standby database to be the next primary database after a switchover or a failover, there are several factors to consider. Any broker configuration name that is referred to must exist in the configuration declaration section. It is important that all SRVCTL add service options be identical on all the databases so that the services behave the same way before and after a role change. Fast-start failover will not be attempted for the other types of database shutdown (NORMAL, IMMEDIATE, TRANSACTIONAL). PRIM>STARTUP MOUNT; The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. The time interval specified by the FastStartFailoverThreshold property is ignored if the master observer detects that a user-configurable condition has occurred or if a fast-start failover has been requested by the DBMS_DG.INITIATE_FS_FAILOVER function. The service can be started on the physical standby only after the redo generated by starting the service has been applied. name of the observer log file is The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. Transitions the target standby database into the primary database role, as follows: Changes the role of the database from standby to primary. 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. The ObserverReconnect configuration property specifies how often the observer establishes a new connection to the primary database. The observer does not attempt to reinstate the former primary database. 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. value is 10. If the DG_ADMIN environment variable is not set, or the See Troubleshooting Problems During a Switchover Operation for more information. You cannot perform a switchover to a snapshot standby database unless you first convert it back to a physical standby database. Data Guard Failover to physical standby Tips - dba-oracle.com The default name of the observer runtime data file is 3. The state file is locked when the observer is running to prevent multiple observers from using the same file. FAN events are published using Oracle Notification Services (ONS) for all Oracle integrated database clients in Oracle Database 12c and later. 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. For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. Broker Configuration Has Multiple Registered Observers.

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