If clients are already configured to automatically time out and reconnect if they don't get a response from the database, a simple but effective approach is to use a network alias (e.g. If it detects that Flashback Database was disabled, either manually, or automatically because Flashback Database discovered a problem, Broker signals "ORA-16827: Flashback Database is disabled". Log in as a test user and make some changes that won't impact other parts of the system. Some properties have changed between those releases. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: set the ObserverPingInterval and To issue commands and interact with the FB Page:https://www.facebook.com/dbahariprasath/? 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. The primary database, it attempts to disable fast-start failover on as many databases in the configuration with which it has a network connection. This list describes restrictions when fast-start failover is enabled. You can use the SHOW CONFIGURATION WHEN PRIMARY IS command to show the redo transport configuration (based on each member's setting of the RedoRoutes property) that would be in effect if the specified database were the primary database. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL. 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. Verifies that the target standby database is enabled. These are the guidelines for choosing a target standby database. Verify the target standby database is ready for failover. Restore - Flashback Database restores the datafiles to the closest snapshot prior to the specified SCN. You must then re-create it from a copy of the new primary database and reenable it as described in How to Re-create and Reenable a Disabled Database. This property cannot be used to prevent the primary database from shutting down if a fast-start failover occurred because a user configuration condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. That process is shown here. ObserverPingRetry configuration properties. However, if you want the observer to reconnect to the primary database periodically as a means of testing the health of the network connection to the primary, then use the ObserverReconnect configuration property. If the database is not managed by Oracle Clusterware, 11.2 rac servicefailover - To stop the observer, see Stopping the Observer. For reliable startup, the initial connection should always be made to the primary. The following sections describe these topics: Prerequisites for Enabling Fast-Start Failover, Viewing Fast-Start Failover Configuration Statistics and Status, Performance Considerations for Fast-Start Failover, Reinstating the Former Primary Database in the Broker Configuration, Shutting Down Databases In a Fast-Start Failover Environment. Note: if the observer loses contact with the primary, but the standby does not, the observer can determine that the primary is still up via the standby. This file contains connect identifiers to both the primary and the target standby databases. There are many examples, and Ritesh Chhajer offers this example of doing a Data Guard switchover using dgmgrl: 1. The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. This function can be called from a connection to either the primary or any standby in the configuration. In an Oracle Data Guard configuration, the SRVCTL -startoption and -role are updated after switchover to reflect the current open mode and database role on the new primary and standby databases. Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. Use the callout configuration file and script may allow the primary database to continue redo generation after In the following example, ObserverReconnect is set to 30 seconds. Note that if the V$DATABASE.FS_FAILOVER_STATUS column has a value of DISABLED, then any values returned for the remaining columns related to fast-start failover (V$DATABASE.FS_FAILOVER_*) become irrelevant. Clusterware: The broker notifies Oracle Clusterware to stop active To verify this change, again query the Database_role column of V$DATABASE. crash, data in this file can be used to restart the observer to the Post failover, there are two methods of rebuilding your failed primary Method 1: Rebuild from scratch -> RMAN duplicate Method 2: Flashback database -> only if Flashback was enabled Reinstate failed primary: When you use data guard broker, with just one command, the primary can be rebuilt. When the configuration has more than one registered observer, if the primary and target standby databases stay connected but the connection to the master observer is lost, then the broker tries to nominate a backup observer as the new master observer. is only possible when the configured data loss guarantee can be maximum availability and maximum performance modes, to avoid a FastStartFailoverLagLimit property. SQL> Select Database_role from v$Database; Observer sites monitor the fast-start failover environment. In this case fast-start failover cannot occur because the databases are not ready to failover. Sign in to Azure There is little risk in enabling Flashback Database to determine its storage requirements - it can be disabled while the primary is open if necessary. Initiate the failover on the standby database STAN: You can also query the V$FS_FAILOVER_STATS view to display statistics about fast-start failover occurring on the system. ObserverPingRetry properties before Observers should be installed and run on a computer system that is separate from the primary and standby systems. Complete Failovers in Configurations Using Cascaded Standbys. An existing connection which is already closed from the database side would throw an error. US Coast Guard Auxiliary. Displays only on the target standby database when either the primary or target standby database was shut down in a controlled fashion (using the NORMAL, IMMEDIATE, or TRANSACTIONAL, options, but not the ABORT option). If that metadata is pushed out, Oracle can no longer find a fuzzy snapshot so it will not be able to flash back. Enable Fast-Start Failover Using Cloud Control. Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. An application should use caution when calling the DBMS_DG.INITIATE_FS_FAILOVER function because the observer will initiate failover, if at all possible. the observer on ob2-host to become the master Database hosts are referred to as "a" and "b" hosts and the databases themselves are referred to as the "a" and "b" databases. 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. Therefore, the target standby never falls behind the primary For manual failover, the observer is started and communicating with the target standby database. How to reinstate the old Primary as a Standby after Failover in #Oracle On Windows, the directory specified by the DG_ADMIN It also requires Flashback Database to be enabled on both the primary and target standby databases. To switchover to a standby that is not the current failover target: John Smiley [jrsmiley@gmail.com] is a persistent storage architect for a major online retailer. How to switch roles in Oracle Data Guard - The Geek Diary For example: Using DGMGRL, you can do this by examining the output of the SHOW CONFIGURATION LAG. The MASTEROBSERVERHOSTS, DGMGRL reports an error if the data (in seconds) specified by the If the primary database does not have connectivity with the target standby database, fast-start failover remains enabled on the target standby database and the observer may still attempt a fast-start failover if conditions warrant a failover. By choosing the standby database with the least amount of unapplied redo, you can minimize the overall time it takes to complete the switchover operation. Whether or not you need the FORCE option depends mostly on if the primary and target standby database have network connectivity: If the primary and target standby database have network connectivity, and the database to which you are connected has network connectivity with the primary database, the FORCE option has no effect. configuration named ConfigurationSimpleName. select name,open_mode,database_role from v$database; Note: What is true about Data Guard setup with fast-start 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. 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. ), The RedoRoutes property on a far sync instance if it is being used to receive redo from the primary database and ship redo to the target standby database, The standby database that is the target of fast-start failover, A far sync instance if it is being used to receive redo from the primary database and ship redo to the target standby database, Unless the conditions listed in Performing Manual Role Changes When Fast-Start Failover Is Enabled have been met, To a standby database that is not configured as the fast-start failover target. the primary database and the target standby database do not have a network 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). created under this directory by DGMGRL will also have the same permissions. If a fast-start failover was initiated because the primary database had crashed or lost connectivity with the master observer and target standby database, then the master observer automatically attempts to reinstate the former primary database as a standby database, if the FastStartFailoverAutoReinstate configuration property is set to TRUE.