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the observer was killed after the stall began, but before the failover timeout had elapsed). crash, data in this file can be used to restart the observer to the The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. Switchover Steps. 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. 11.2 rac servicefailover 2020-01-28 ORACLE ORACLE RAC/ASM RAC112. For example: Fast-start failover occurs if both the observer and the target standby database lose connection to the primary database for the period of time specified by the FastStartFailoverThreshold configuration property. A broker configuration can belong to multiple groups. In this mode, no actual changes are made to your Broker configuration. (Snapshot standbys are not included in the table because they are not supported as fast-start failover targets.). If these parameters are modified outside of Broker, it raises a warning. Rather, fast-start failover will be enabled in accordance with the current protection mode. times that the observer retries a failed ping before it initiates a Only the master observer can coordinate fast-start failover with Data Guard broker. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. In this case, the observer cannot perform a fast-start failover even if conditions warrant a failover. Event notification and database connection failover support is available to database clients connected to local database services when a broker-managed failover occurs. In this case fast-start failover cannot occur because the databases are not ready to failover. In an Oracle Data Guard configuration, the SRVCTL -startoption for a standby database is always set to OPEN after a switchover. 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. Many customers use Oracle Database deployed on Amazon Elastic Compute Cloud (Amazon EC2) to run their Oracle E-Business Suite applications. After step 1 finishes, Switch the original physical standby db STAN to primary role; FSFO can also be used with logical standbys and an FSFO-enabled configuration may have multiple standbys with a mix of physical and logical, but only one standby can be the failover target at any given time. The broker allows a complete failover to proceed as long as there are no errors present on the standby database that you selected to participate in the failover. Note that a switchover operation may be started before the specified wait 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. It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). SET MASTEROBSERVER TO allows you to manually change the observer configuration file. miliseconds. primary, only the observers specified in the property can be use in the SET may allow the primary database to continue redo generation after To stop a specific observer when there are multiple registered observers running, issue the following command: You can log into DGMGRL from any machine to stop an observer. Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. The former primary database is disabled. Broker maintains these parameters by issuing ALTER SYSTEM commands as appropriate during role transitions, database startup/shutdown, and other events. ORACLE instance shut down. Note that the new primary database does not need to be restarted. 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. To verify this change, again query the Database_role column of V$DATABASE. WAIT option, broker waits for the amount of POTENTIAL DATA LOSS: Fast-start failover is enabled with some data loss. It's a good idea to have at least two hosts configured to run observers so that one can take over if the other fails. 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. Use the wrapper script to start the observer process when the observer host boots or to restart it if it dies. Starting Observers as Background Processes. The broker allows an immediate failover to proceed even if there are errors present on the standby database that you selected to participate in the failover. A fast-start failover to the target standby database fails. When fast-start failover is disabled, no observer is called the master observer; all observers have the same functionality. In these sample commands, the ellipse () signifies any other add service options you wish to supply. fsfocallout.ora. In maximum protection mode, set the LogXptMode database property to SYNC (note that in maximum protection mode, a far sync instance cannot be used to ship redo to a standby). ObserverPingRetry configuration properties. 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. The OberverPingRetry property specifies the number of Your email address will not be published. When restarting the databases, you may restart them in any order. If there is more than one standby database in the configuration, you must explicitly set the FastStartFailoverTarget property on the primary database to name one or more candidate target standby databases. Oracle Dataguard : Switchover VS Failover - LinkedIn Choosing the standby database with the smallest transport lag can minimize the amount of data loss and in some cases, incur no data loss at all. 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. The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. This property also affects whether the broker skips viability checks of bystander standby databases when a fast-start failover occurs. A high lag limit may lead to more data loss but may lessen the performance impact of the primary database. file, observer runtime data file (fsfo.dat), fast-start failover callout New sql server failover cluster installation greyed outtrabajos Oracle Data Guard 11gR2 Administration : Beginner's Guide Specifying the Observer Configuration File. It is not reversible. directory does not have the required permissions. If the client uses remote ONS subscription, the client must specify the hostname and port of the ONS daemon(s) of the primary database and each standby database. FastStartFailoverAutoReinstate is set to FALSE, Another failover or switchover occurred after the fast-start failover completed but before the former primary database restarted, The master observer cannot connect to the former primary database, The former primary database cannot connect to the new primary database, The former primary database and the new primary database are not configured in the same fast-start failover environment, The former primary database was disabled because of a manual failover when fast-start failover was disabled. Written by authors well-known for their talent with RAC, Pro Oracle Database 11g RAC on Linux . When fast-start failover is enabled, the primary and standby randomly choose one of the registered observers to be the master. If the database is not enabled, you will not be able to perform a failover to this database. If only a path is specified, the files are Manual failover can be performed even if the pre-condition checks are not met. If the primary database is an Oracle Real Application Clusters (Oracle RAC) database, the master observer will attempt to connect to one of the remaining primary instances. Add the primary database and each standby database to the address list. operation can be automated using callout scripts. Observer sites monitor the fast-start failover environment. They can all be done at the same time in a single bounce. During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. The primary database can be opened even if there is no acknowledgement from the observer or target standby. Application calls to DBMS_DG.INITIATE_FS_FAILOVER. database that has the least amount of unapplied redo (smallest apply lag). North_Sales is in the primary role. This section describes how to configure and verify each prerequisite. occurred to the target standby database prior to disabling fast-start Chapter 9 of the Data Guard Broker documentation (10g and 11g) contains a description of each property. When you configure data guard using OCI console, the default mode is set to maxprotection. There are normally two situations when this operation will be performed: a planned outage for maintenance of the primary database or disaster recovery. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. 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. The DB_ROLE_CHANGE event will fire whenever a database is opened for the first time after a role transition. 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. Therefore, the target standby never falls behind the primary The database cannot provide fast-start failover status information. Broker can be configured to initiate failover on any of the following conditions. callout directory. configuration scripts and checks for errors or misconfigurations. databases (PDBs) on any of the instances. enabling fast-start failover. You must specify it every time you start a new DGMGRL client. In the media recovery phase, Flashback Database applies redo to bring the database up to the standby_became_primary_scn. If the configured data loss guarantee cannot be upheld, Verifies that the primary and the target standby databases are in the following states: The primary database is enabled and is in the TRANSPORT-ON state. Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). Oracle Data Guard is a solution provider to businesses by offering data protection and its disaster recovery along with its high availability. 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. Reinstating the Former Primary Database in the Broker Configuration for more information about reinstatement. Switching over to a logical standby database results in the snapshot and physical standby databases in the broker configuration being disabled by the broker, making these databases no longer viable as standby databases. FB Page:https://www.facebook.com/dbahariprasath/? You cannot create the standby DB system in a different AD from the primary DB system. Ensure that the required permissions are granted to the DG_ADMIN Now it will return PRIMARY. the names of the scripts created in the previous step. After the broker receives the STOP OBSERVER request, the request is passed to the observer the next time the observer contacts the broker, and the observer then stops itself. is guaranteed to lose no more than the amount of A far sync instance or Zero Data Loss Recovery Appliance is not a database and therefore cannot be the target of a role transition. files to automate tasks that must be performed before and after a fast-start failover The observer immediately initiates a fast-start failover, as long as the failover target database is in a valid fast-start failover state ("observed" and either "synchronized" or "within lag") to accept a failover. the location of the observer log file, and the location of the observer runtime data Use the oraenv script provided by Oracle. Do not attempt to reinstate the old primary database if an ORA-752 or ORA-600 [3020] error has occurred at the failover target. File. You must also start and stop the SALESRO service on the primary so that it can be started on the standby. After a failover, the broker publishes Fast Application Notification (FAN) events. Although redo transfer is synchronous, Maximum Availability mode allows the primary to remain available if the standby database becomes unavailable for any reason (e.g. 3. It's good practice to use separate listeners for application connections and Data Guard connections. The following example displays the contents of the fast-start failover Except for testing purposes, it is not recommended that you start more than one observer on the same host for a Data Guard broker configuration. 3. Now it will return PRIMARY. For each observer, the V$FS_FAILOVER_OBSERVERS view provides the The During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. This allows Data Guard to remain functional during maintenance periods when the application listeners are down. There are many examples, and Ritesh Chhajer offers this example of doing a Data Guard switchover using dgmgrl: 1. Monitoring flashback database history and reacting when it drops below 30 minutes will save you time and improve availability. Valid values are >= 100. These conditions are described in the following table: Dictionary corruption of a critical database. Contains the observer runtime data file for the broker See Choosing a Target Standby Database for helpful advice. Otherwise, they must be re-created from a copy of the new primary database. Oracle 11g Manual Data Guard Part-II - DBAtricksWorld.com See Oracle Data Guard Concepts and Administration for information about tuning the log apply rate for a physical standby database. the SYSDG or SYSDBA privilege. 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. 1 second. For more details about managing Redo Apply services using properties, see Managing Log Apply Services. pre-callout configuration script and post-callout configuration script. 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 . This action may result in two databases in the configuration simultaneously assuming the primary database role. The following is an example of querying the V$FS_FAILOVER_STATS view: Disabling fast-start failover prevents the observer from initiating a failover to the target standby database. observer. If the failover target is a logical standby database, the original primary database and all physical and snapshot standby databases in the configuration will be disabled. The primary and target standby must have connectivity for the STOP OBSERVER command to complete successfully. property. Thus, the command-line prompt on the observer computer does not using the same SYS credentials you used when you connected to the Broker changes database parameters during startup and role transitions via ALTER SYSTEM commands. Use Recovery Manager (RMAN) to back up the PeopleSoft database on a regular backup schedule. SUSPENDED is cleared when connectivity with the primary database is restored. If you performed a failover or switchover that requires you to re-create the failed primary database or standby databases that were disabled during the role transition, then follow the procedures in the Oracle Data Guard Concepts and Administration chapter, "Creating a Physical Standby Database" and also the Oracle Data Guard Concepts and Administration chapter, "Creating a Logical Standby Database.". Unless action is taken to change the failover target to one of the bystanders, the new primary will be without a failover target until the former primary is reinstated as a standby. from another DGMGRL session. If Flashback Database history is insufficient, the observer will not be able to reinstate and you will have to manually reinstate from backup or by primary duplication. Verify there are no active users connected to the databases. Starting with 10.2.0.4 (including all versions of 11g and later), Oracle provides the FastStartFailoverPmyShutdown Broker property that allows you to specify what the primary should do if it is still in a stalled state when the FSFO threshold timeout has elapsed. SQL> Select Database_role from v$Database; You will then need to re-create the physical standby databases from a copy of the new primary database before you can reenable them. An application should use caution when calling the DBMS_DG.INITIATE_FS_FAILOVER function because the observer will initiate failover, if at all possible. This database property is used to specify how the observer should connect to and monitor the primary and standby database. If the configuration contains physical, snapshot, and logical standby databases, consider choosing a physical standby database as the target standby database. Instead, when broker notifies the Oracle It uses these databases as a copy of the . Broker keeps its configuration details in flat file. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. 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. Observers continuously monitor the fast-start failover environment to ensure the primary database is available (described in When Fast-Start Failover Is Enabled and the Observer Is Running). To verify the observer is started and the configuration is ready for In maximum availability mode, the behavior depends on the value of the This is typically done for planned maintenance of the primary system. If the DG_ADMIN environment variable is not set, or the (For example, if the DBMS_LOGSTDBY.SKIP procedure was used to specify which database operations done on the primary database will not be applied to the logical standby database.). physical standby database. It has two parts in the following order: Configuration declaration this section is mandatory. Create a wallet and set the default username and password to the database's SYSDBA credentials (usually SYS). FastStartFailoverLagLimit property. When performing a failover in a configuration whose standbys are all of the same type, choose the standby database that has the smallest transport lag. You might, for instance, use this to allow the observer to monitor the databases using the same connect identifiers as the client applications. Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs Determine the number and size of the Online Redo Log files (ORLs). Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. We'll start with switchovers. In The RedoRoutes property on the primary if the new value would result in the primary not being able to ship redo to the current fast-start failover target standby.