data guard failover steps
the location of the observer log file, and the location of the observer runtime data See Troubleshooting Problems During a Switchover Operation for more information. ), 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. It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. SHOW OBSERVER command to confirm that the switch took place. The command SHOW OBSERVER provides detailed information about registered observers. Observer sites monitor the fast-start failover environment. Were sorry. For example: Scenario 6: Enabling Fast-Start Failover and Starting the Observer. 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. If the Oracle Data Guard configuration is operating in maximum protection mode, the broker does not allow a switchover to occur to a logical standby database. file also declares broker configurations and defines configuration PDBs. Stopping the observer does not disable fast-start failover. To install Oracle Data Guard, you need to create two Azure VMs on the same availability set: The primary VM (myVM1) has a running Oracle instance. Simply use DISABLE FAST_START FAILOVER. Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database: . ConfigurationSimpleName is created. same permissions. If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. Before enabling fast-start failover, use one of the following techniques The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. By default, the observer uses the same connect identifiers used by Data Guard for redo transfer and information exchange between the primary and standby ( DGConnectIdentifier in Oracle Database 11g, InitialConnectIdentifier in Oracle Database 10g). Data Guard broker does not manage or store credentials. required permissions, the admin folder is created Step-by-step instructions for manual reinstatement are described in Reenabling Disabled Databases After a Role Change. Use Cloud Control or DGMGRL to perform either a complete (recommended) or an immediate failover. Starting with Oracle Database Release 21c, use the DG_ADMIN performance protection mode with fast-start failover. If you intend to switch back to the original primary database relatively soon, you may allow the physical and snapshot standbys to remain disabled. At a minimum, you must set db_unique_name. If it exists, and it contains a pre-callout script location, 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. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. The list is empty by default. It is also possible to initiate failover using the dgmgrl failover command. created when the START OBSERVER command is issued. SQL> startup ORACLE instance started. 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. It also requires Flashback Database to be enabled on both the primary and target standby databases. You can find detailed information about all observers, including master observers and backup observers, in the V$FS_FAILOVER_OBSERVERS view. By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. If the currently configured mode is maximum protection, Cloud Control will downgrade the mode to maximum availability. To disable fast-start failover, use the Fast-Start Failover wizard in Cloud Control or the DGMGRL DISABLE FAST_START FAILOVER [FORCE] command. It's generally a good idea to store the state file in a directory associated with the database to avoid locking issues when running multiple observers on the same host. 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. Note that a switchover operation may be started before the specified wait Therefore, the primary database can continue processing transactions, even if the target standby database fails. Oracle Data Guard configuration with DGMGRL. 2) Switchover/Failover option is disabled on Enterprise Manager.What are the steps to enable it so that I can do Switchover/Failover operation using OEM. If the target is a snapshot standby database, the broker first converts the database to a physical standby database. See Sources of Diagnostic Information for details about the broker's drc* log files. 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. Another good test is to simulate network failures that leave the primary up, but isolated from the failover target standby and the observer. Media Recovery - Once the restore is complete, recovery proceeds as a typical media recovery, applying redo from archived and online redologs and rolling back uncommitted changes with undo. The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. Be sure to include the Data Guard listener in the local_listeners database parameter. 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. Verify the standby database instance is mounted. lag is less than or equal to the value specified by the When fast-start failover is enabled, the primary and standby randomly choose one of the registered observers to be the master. However the target can receive redo from a far sync instance.). Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. The master observer never waits for the threshold to expire to perform a fast-start failover in the following situations: If the master observer determines that any of the user-configurable conditions has been detected, then it attempts a fast-start failover. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). To run an observer as a background process, use the DGMGRL command START OBSERVER IN BACKGROUND. A far-sync instance cannot be used in maximum protection mode. https://www.facebook.com/dbahariprasath/? Disable fast-start failover using the DGMGRL DISABLE FAST_START FAILOVER command. When both databases have been restarted, you may restart the observer. Use the VALIDATE STATIC CONNECT IDENTIFIER command to ensure the static services have been configured correctly. data (in seconds) specified by the The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. Your email address will not be published. Slightly less critical than making sure you've got a good primary is making sure the failed primary can be automatically reinstated. See Performing Manual Role Changes When Fast-Start Failover Is Enabled for more information. 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. files to automate tasks that must be performed before and after a fast-start failover The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. Note the primary and target standby must have connectivity for this command to complete successfully. For example: You can find information about the master observer by querying the V$DATABASE view. Stop the observer using the DGMGRL STOP OBSERVER command. Commands For Managing Observers on Multiple Configurations. A switchover guarantees no data loss. Figure 6-1 shows the relationships between the primary database, target standby database, and observer during fast-start failover: Before Fast-Start Failover: Oracle Data Guard is operating in a steady state, with the primary database transmitting redo data to the target standby database and the observer monitoring the state of the entire configuration. To enable fast-start failover, both the primary and target standby databases must be running and have connectivity, and satisfy all of the prerequisite conditions listed in Prerequisites for Enabling Fast-Start Failover. Flashing back a database is much faster and more seamless (one simple DDL statement) than traditional point-in-time or SCN-based recovery. 3. If the configuration is not failable, the DBMS_DG.INITIATE_FS_FAILOVER function returns an ORA error number (it does not signal an exception) informing the caller that a fast-start failover could not be performed. client-side broker files, the specified values are used. If the PreferredObserverHosts property is set for the current To do this, use the SET ObserverConfigFile and SHOW ObserverConfigFile commands. command does not have a network connection to the primary database. When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. Fast-start failover is inhibited in this case. Ideally the primary, standby, and observer will be in geographically separate areas. Make sure that your OS environment on the standby is setup. See the Oracle Reference and Data Guard Administrator guides for your release for details. through these services to exit or for the specified wait time You can, however, perform a manual failover to a snapshot standby. For Active Oracle Data Guard, it will fail to open up a connection unless its in read-only mode. Table 6-3 FS_FAILOVER_OBSERVER_PRESENT Column of the V$DATABASE View, The master observer is currently connected to the local database, The master observer is not connected to the local database. However failing over to a snapshot standby database will require more time because the broker must first convert it back to a physical standby database. on particular instances based on the service configuration. 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. This results in the observer establishing a new connection to the primary database every 30 seconds. A far sync instance or Zero Data Loss Recovery Appliance is not a database and therefore cannot be the target of a role transition. property. MASTEROBSERVERHOSTS, DGMGRL reports an error if the crash, data in this file can be used to restart the observer to 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. If multiple observers have been started for the configuration, then be sure to specify the name of the observer whose environment is to be patched (STOP OBSERVER observer-name). Enabling fast-start failover and starting an observer process involves the following tasks. occur. Problems with automatic reinstatement are frequently due to misconfiguration, so let's look at this in a bit more detail. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Oracle Data Guard can switch a standby database to the primary role in case a production database becomes unavailable due to . It is then started and stopped on the primary database. FastStart Failover Ensues: Disaster strikes the primary database and its network connections to both the observer and the target standby database are lost. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. by the current operating system user who is running DGMGRL The subdirectories One is the master Reinstatement is supported only after failover in a broker configuration. fsfocallout.ora. You can query the V$DATABASE view to verify that the observer is started and the configuration is ready for fast-start failover. Use the 'show fast_start failover' command to see which user configurable FSFO failover conditions are in effect. Queries and DML will continue to run - only sessions that commit will block. failover to the target standby database. file (fsfo.dat). If necessary, you can shut down the primary or target standby database in a fast-start failover environment. Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs That is, if the observer is connected to any instance in the Oracle RAC, all instances will show a value of YES. Only the master observer can coordinate fast-start failover with Data Guard broker. is guaranteed to lose no more than the amount of However, you do have the option of specifying a name and location for the observer configuration file. A fast-start failover occurred because a user-configurable condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. 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. Es gratis registrarse y presentar tus propuestas laborales. If you initiated a complete failover and it fails, you might need to use immediate failover. Application Continuity is supported for Oracle Data Guard switchovers to physical standby databases. Remote login is required, along with a password file, to allow the databases in a Data Guard configuration to connect to each other. Since the observer is a specialized instance of a dgmgrl session, the observer host should be installed with either the Oracle Client Administrator software or the full Oracle Database software stack. Immediate: No additional data is applied on the standby database, resulting in a data-loss . The minimum value of ObserverPingInterval is 100 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. Configure the protection mode. Set both these properties to achieve a primary failure detection time of 1 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. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by To override this behavior and allow a fast-start failover to occur if the observer is unable to contact the primary for more than FastStartFailoverThreshold seconds, set the ObserverOverride property to TRUE. For this reason, you should first issue this command on the target standby database. 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. Default value is 10 miliseconds. There are prerequisites that must be met before the broker allows you to enable fast-start failover. The most common problems are mismatched Data Guard protection modes and LogXptMode properties and forgetting to enable Flashback Database on the primary or standby. The configuration and database status report that the observer is not running and return one of the following status messages: While the configuration is in the unobserved state, fast-start failover cannot happen. Starting the Observer as a Background Process Using The observer automatically starts the reinstatement process. OBSERVER command, if this directory does not have the 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. You can start the observer before or after you enable Most of the network services used in a FSFO environment may use dynamic registration, but to enable Broker to restart instances during role transitions or during reinstatement after a failover, you must define a static service named db_unique_name_dgmgrl. The observe-only mode for fast-start failover enables you to test how fast-start failover will work in your environment. Broker checks to see if Flashback Database is enabled on the primary and failover targets when FSFO is enabled. The environment is a single instance database without any grid Infrastructure components. Fast-start failover can incur data-loss within the time specified by FastStartFailoverlagLimit. If you want to use one Oracle home to start multiple observers, with each observer monitoring a different fast-start failover configuration, use the FILE qualifier to specify a unique observer configuration file location for each configuration to be monitored. Unlike ORLs, SRLs should be created with only one member per group. The word manual is used to contrast this type of failover with a fast-start failover (described in Fast-Start Failover). This allows for redundancy in your Data Guard observer setup as well. SET MASTEROBSERVER TO allows you to manually change the observer configuration file. Oracle 12c-Step by Step Manual Data Guard Switchover, Manual Upgrading Oracle Database From 11.2.0.4 to 12.2.0.1, Automatically Terminated The Blocking Session By Setting MAX_IDLE_BLOCKER_TIME, Apply Patching On Oracle 21c Database Release Update 21.7.0.0.0, Oracle 21c Point In Time Recovery of Pdb Database, Oracle 21c Cloning a PDB Database Using Sqldeveloper Tool. In order for Flashback Database to succeed, there must be sufficient history available in the Flashback Database logs and all of the redo generated between the restore point and the standby_became_primary_scn must be available. You can disable fast-start failover if necessary, by using the FORCE option. 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. miliseconds. Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. ERROR: Unable to verify the graphical display setup. In short, the failover is the deformation of the production (primary) database and activating standby database as the primary. 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. Verify there are no active users connected to the databases. If you want to capture any logging generated by the observer, use the LOGFILE IS option on the START OBSERVER command, and ensure that the file name is unique. Many customers use Oracle Database deployed on Amazon Elastic Compute Cloud (Amazon EC2) to run their Oracle E-Business Suite applications.