data guard failover steps

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. Application calls to DBMS_DG.INITIATE_FS_FAILOVER. Create a trigger based on the, Oracle Database PL/SQL Language Reference, Choosing a Target Standby Database for Switchover, Choosing a Target Standby Database for Failover, Scenario 9: Performing a Switchover Operation, Scenario 10: Performing a Manual Failover Operation, Database Service Configuration Requirements, Troubleshooting Problems During a Switchover Operation, How the Broker Performs a Complete Failover Operation, How the Broker Performs an Immediate Failover Operation, Setting the Protection Mode for Your Configuration, Scenario 7: Enabling Fast-Start Failover When a Far Sync Instance Is In Use, Description of "Figure 6-1 Relationship of Primary and Standby Databases and the Observer", Enabling Fast-Start Failover Task 7: Configure Actions Before and After Fast-start Failover (Optional), Directing a Fast-Start Failover From an Application, Fast-start Failover Callout Configuration Files, Oracle Data Guard Command-Line Interface Reference, Description of "Figure 6-2 The Observer in the Fast-Start Failover Environment", Oracle Enterprise Manager Command Line Interface. An observer can be moved from one computer to another through a process of stopping it on one system and and re-starting it on another. FastStartFailoverLagLimit property. 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. 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. 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. An observer process is integrated in the DGMGRL client-side component of the broker and typically runs on a different computer from the primary or standby databases and from the computer where you manage the broker configuration. By default the file is named fsfo.dat and is created in the working directory where the observer is started. It comes with a GUI and command line interface. Suppose you have a primary database, BOSTON, and a standby database, CHICAGO. become the master observer. The observer is very lightweight, requiring few system resources. $DG_ADMIN directory. If the standby database's redo applied point is within that many seconds of the primary database's redo generation point, a fast-start failover will be allowed. Broker will set the primary to use asynchronous log transport by default. ensure that it has the required permissions. 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 switchover guarantees no data loss and is typically done for planned maintenance of the primary system. Notice that the terminal session appears to hang after starting the observer. flashback logs on that database. See Manual Failover for information about manual failover. 3. We suggest you try the following to help find what youre looking for: This document will guide you through configuringOracle Data GuardFast-Start Failover (FSFO) using a physical standby database. observers for a single Data Guard configuration. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. PDBs. Create a unique connect alias for each database. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. To stop the observer, see Stopping the Observer. An immediate failover should only be performed when a complete failover is unsuccessful or in the error cases just noted. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. You can disable fast-start failover if necessary, by using the FORCE option. When a fast-start failover occurs because either a user configurable fast-start failover condition is detected or an application initiates a fast-start failover by calling the DBMS_DG.INITIATE_FS_FAILOVER function, the former primary database is always shut down and never automatically reinstated. The command SHOW OBSERVER provides detailed information about registered observers. list of the observers that can become the master observer when that Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. The target standby database has contact with the primary database. /home1/dataguard/config_NorthSales/callout/fsfocallout.ora. the observer on ob2-host to become the master The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. In the media recovery phase, Flashback Database applies redo to bring the database up to the standby_became_primary_scn. PRIM>SHUTDOWN IMMEDIATE; With FSFO enabled, Broker expects to find an observer, which we haven't started yet, so if you verify the at this point with 'show configuration', Broker will report a warning (if it doesn't, give it a minute to discover that the observer isn't there). 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. For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. occur. committing because a fast-start failover may have occurred while it was Only the observer can initiate FSFO failover. For reliable startup, the initial connection should always be made to the primary. To issue commands and interact with the The command SHOW FAST_START FAILOVER shows a list of registered observers and indicates which one is the master. Use synonyms for the keyword you typed, for example, try "application" instead of "software.". The steps in this section describe the tasks involved to perform a manual failover. Another good test is to simulate network failures that leave the primary up, but isolated from the failover target standby and the observer. enabling fast-start failover. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. Manual Failover in Data Guard - ORACLE-HELP 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. DGMGRL to manage multiple observers on multiple configurations. How to reinstate the old Primary as a Standby after Failover in #Oracle 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. All other registered observers are considered to be backup observers. The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the 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. Figure 6-2 The Observer in the Fast-Start Failover Environment. The observer is perfectly satisfied if all of the redo it needs to meet your durability requirements has been received by the failover target. You must also start and stop the SALESRO service on the primary so that it can be started on the standby. When restarting the databases, you may restart them in any order. As mentioned above, Maximum Availability mode is mandatory for Oracle Database 10g and optional for Oracle Database 11g. Make some new changes and verify that they are preserved after failover. If a non-zero value is specified for the fsfocallout.ora. Displays if the standby database's redo applied point lags the primary database's redo generation point by more than the number of seconds specified by the FastStartFailoverLagLimit configuration property and the configuration is operating in maximum performance mode. They must be re-created before they can serve as standby to the new primary database. If only a path is specified, the files are primary database must have network connectivity. For example, to determine if fast-start failover can occur, the FS_FAILOVER_STATUS column displays either SYNCHRONIZED or TARGET UNDER LAG LIMIT and the FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. Example 6-2 Sample Observer Configuration File. Indexing is a mechanism by which the underlying data is mapped for faster retrieval. PRIM>connect /@PRIM as sysdba Then, on the Fast-Start Failover Change Mode page, click Enabled. the primary and target standby databases. DGConnectIdentifier, "Scenario 9: Performing a Switchover Operation" for an example of using the VALIDATE DATABASE command to show a database's readiness to complete a role switchover, "Scenario 10: Performing a Manual Failover Operation" for an example of using the VALIDATE DATABASE command to show a database's readiness to complete a role failover. The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. This means that in order for a flashback database operation to succeed, observer and the standby both lose contact with the primary. Once Flashback Database has succeeded, the observer will convert the database to a standby, bounce it, and begin apply services. 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. If fast-start failover is disabled, then manual failover may still be possible. This list describes how the overall Oracle Data Guard protection mode is handled after a manual failover (complete or immediate). The price for this guarantee is increased commit latency ( log file sync waits). In this example, the original primary data is called PRIM and the original standby database is called STAN. directory does not have the required permissions, broker does the following: When you run DGMGRL commands, if a path and file name are explicitly specified for directory. 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. The simplest way to do this is to abort the primary. However, the event notifying a failover is only published for database services that have been configured to be active while the database is in the primary role on the new 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. Craigslist Corpus Christi Jobs Skilled Trades, Articles D