Restarts the new standby (former primary) database if the switchover occurs to a physical standby database, and Redo Apply begins applying redo data from the new primary database. You can manually stop a specific observer or all observers. An existing connection which is already closed from the database side would throw an error. To perform specified actions before or after a fast-start failover Slightly less critical than making sure you've got a good primary is making sure the failed primary can be automatically reinstated. The observer does not attempt to reinstate the former primary database. But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). environment variable must have exclusive permissions wherein it can be accessed only The same process should work for RAC environment as my colleague has . Set both these properties to achieve a primary failure detection time of 1 Testing FSFO failover requires simulating loss of the primary. If necessary, you can shut down the primary or target standby database in a fast-start failover environment. performance protection mode with fast-start failover. Oracle Database 11g FSFO adds support for Maximum Performance mode (async redo transfer), providing the flexibility to trade durability for performance. Configure the TNSNAMES.ORA file on the observer system so that the observer is able to connect to the primary database and to the pre-selected target standby database. The steps in this section describe the tasks involved to perform a manual failover. The values that indicate FSFO is ready for failover are listed below. If reinstatement of a database fails, its status changes to ORA-16795: the standby database needs to be re-created. change tracking enabled, broker enables block change tracking on the new configuration file, such as START OBSERVING, Ensure this file cannot be read by unauthorized users. ConfigurationSimpleName represents The default group is all the configurations defined in the observer configuration file. Do not attempt to reinstate the old primary database if an ORA-752 or ORA-600 [3020] error has occurred at the failover target. This walkthrough uses Maximum Availability mode to achieve "zero data loss". After FSFO is enabled, Broker will continue to check that Flashback Database is enabled during health checks. You cannot perform a manual failover to the target standby database for the same reason. The failed primary database requires reinstatement as a new standby database to the new primary. The FORCE option may be the preferred method for disabling To restore your original disaster-recovery solution after switchover to a logical standby database or after failover to any standby database, you may need to perform additional steps. 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. Use synonyms for the keyword you typed, for example, try "application" instead of "software.". Add the SRLs. (Oracle Call Interface) client that connects to the primary and target standby databases After Fast-Start Failover: The fast-start failover has completed and the target standby database is running in the primary database role. directory. The broker may not be able to disable fast-start failover on all databases in the broker configuration when you issue the DISABLE FAST_START FAILOVER FORCE command. The simple tests described in this guide are fine for making sure the basics are working, but you'll probably want to develop a more comprehensive set of tests suited to your environment and requirements. A complete failover is the recommended and default failover option. connection, or the database on which you issued the disable fast-start failover In Oracle RAC configurations, the Inaccessible Logfile and Stuck Archiver health conditions may only be applicable to a single instance. lose no more than the amount of data (in seconds) specified by the If there is another standby database that is available for failover, you can perform a manual failover to that standby database after you first disable fast-start failover using the FORCE option on that standby database. The default name of the callout configuration file is The logs also contain other details about the actions that will be performed in case of a failover. The broker initiates a failover after the number of seconds specified by this However, fast-start failover cannot occur when the target standby database is in an unobserved state. See the Cloud Control online help for more information. This article - the seventh in this ongoing . This includes the following: broker configuration is in UNSYNC or LAGGING state or unobserved state, failover target is invalid, reinstatement is in progress, or a master observer switch is in progress. Change Standby to Primary Database. Enabling fast-start failover and starting an observer process involves the following tasks. 1. 1. In maximum protection mode, an automatic failover is always possible because the Because the broker performs the failover after converting the snapshot standby database to a physical standby database, it is likely that all standby databases in the configuration will still be available as standby databases to the new primary database after the failover operation completes. FastStart Failover Ensues: Disaster strikes the primary database and its network connections to both the observer and the target standby database are lost. 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.". The other configurations that are not required but they might make your fast-start failover go smoothly. During the failover to the physical standby database, the Oracle 11g DGB performs the following steps: First, it validates that the target standby database is ready to accept the primary role. If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. OBSERVER command, if this directory does not have the However, you can change the name or the location of the file if you start the observer using the DGMGRL START OBSERVER command and include the FILE IS qualifier. That process is shown here. For reliable startup, the initial connection should always be made to the primary. the ObserverPingRetry and ObserverPingInterval properties to achieve Enable Fast-Start Failover Using Cloud Control. about starting the observer as a background The standby VM (myVM2) has the Oracle software installed only. *PATCH V3 0/6] ASoC: codecs: Add Awinic AW883XX audio amplifier driver [not found] <000701d8e7521f78bc05e6a340awinic.com> @ 2022-11-11 11:26 ` wangweidong.a 2022-11 . Use the wrapper script to start the observer process when the observer host boots or to restart it if it dies. Use Broker's "show configuration" command to determine FSFO status and the "show database statusreport" command to drill down for details if Broker reports a problem. Stopping a Specific Observer When There are Multiple Observers. Oracle Data Guard Concepts and Administration provides information about setting up the databases in preparation of a switchover. Attempt to open the primary database, or the following error may be returned: This error may return if the fast-start failover validity check fails or does not complete in under two minutes. Stops Redo Apply or SQL Apply on the standby database immediately, without waiting until all available redo data has been applied. These tasks assume that you are connected as SYS or SYSDG and that a primary and standby database are already set up in a broker configuration. See the START OBSERVER command for more information. Although the default value of 30 seconds is typically adequate for detecting outages and failures on most configurations, you can adjust failover sensitivity with this property to decrease the probability of false failovers in a temporarily unstable environment. (Snapshot standbys are not included in the table because they are not supported as fast-start failover targets.). the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . When DGMGRL starts, if the DG_ADMIN For manual failover, the observer is started and communicating with the target standby database. Oracle Database 11g adds the ObserverConnectIdentifier database property to the Broker configuration, allowing you to specify a connect identifier for the observer to use for monitoring the primary and failover target. primary database must have network connectivity. To disable fast-start failover, use the Fast-Start Failover wizard in Cloud Control or the DGMGRL DISABLE FAST_START FAILOVER [FORCE] command. this script is run before the fast-start failover is initiated. database is in the primary role. Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option. The previous examples dealt with setting up only one service on a database. All standbys other than the failover target are considered bystanders (v$database.fs_failover_status = 'BYSTANDER'). If the value is non-zero, failover is possible any time the standby database's apply This lets you take advantage of the broker's This prevents a "split brain" condition if a failover occurs since none of the changes made to the isolated primary can be made permanent. Suppose you have a primary database, BOSTON, and a standby database, CHICAGO. Any apply delay must be removed before beginning a switchover. The default name for SET MASTEROBSERVER TO allows you to manually change the observer configuration file. Don't initiate failover unless at least 30 minutes of history is available. See the START OBSERVER If no name is specified for the observer then a default observer name, the host name of machine where the START OBSERVER command is issued, is used. It is instructive to watch the alert logs on both databases as well as the observer log after aborting the primary to gain insight into what happens during FSFO failover. Standby databases that are disabled during switchover, manual failover, or fast-start failover will not be automatically reinstated. 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. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. DG BrokerDG BrokerData Guard BrokerOracleDGRMAN Duplicate . STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. Another consequence of immediate failover is that all other databases in the configuration are disabled and must be reinstated or re-created before they can serve as standby databases for the new primary database. There's a big difference between a system that's FSFO enabled and one that's FSFO ready. database's redo generation point by more than the value specified by the A complete failover can occur without any data loss, depending on the destination attributes of redo transport services, but an immediate failover usually results in some data loss. If the standby database is not enabled for management by the broker, then the failover cannot occur. It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. ERROR: Unable to verify the graphical display setup. 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. Then the STOP OBSERVER command can be issued successfully on the former master observer. There are normally two situations when this operation will be performed: a planned outage for maintenance of the primary database or disaster recovery. See Manual Failover for information about manual failover. Immediately after issuing command in step 2, shut down and restart the former primary instance PRIM: The new primary database starts transmitting redo data to the new standby database. In this mode, the FastStartFailoverLagLimit configuration property is set to zero. operation can be automated using callout scripts. Waits for the target standby database to finish applying any unapplied redo data before stopping Redo Apply (if the target is a physical standby database) or SQL Apply (if the target is a logical standby database). You want to prevent fast-start failover from occurring because the primary database will resume service soon. For example: Using DGMGRL, you can do this by examining the output of the SHOW CONFIGURATION LAG. This exercises the configuration, but triggers failover differently than losing contact with the primary. In cases where This directory is created when you run the db_domain . Alternatively, you can query the V$DATABASE view on the target standby database. status before the crash. While Oracle 11g's Data Guard definitely protects a database when the entire production site is lost via its failover capabilities, it's still necessary for an Oracle DBA to intervene to complete the failover process. Database services can be configured to be active in specific database roles on Oracle RAC databases and on single-instance databases managed by Oracle Restart. RMAN will copy the spfile from the primary, so this init.ora file is only needed during the first phase of the duplication. Verify the standby database instance is mounted. time specified in the WAIT option. To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. command does not have a network connection to the primary database. In this example, the original primary data is called PRIM and the original standby database is called STAN. connectivity with target standby. 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. You can use this information to identify ahead of time any redo transport configurations that would be incorrect after a role change, including any standbys that will not receive redo because the RedoRoutes property was not configured correctly. If the PreferredObserverHosts property is set for the current You can specify particular conditions for which a fast-start failover should occur using either Cloud Control or the DGMGRL ENABLE FAST_START FAILOVER CONDITION and DISABLE FAST_START FAILOVER CONDITION commands. The syntax for the configuration declaration is: The definition for each broker configuration is: The configuration-name can be different from the name defined in the metadata of the Data Guard Broker configuration. the observer was killed after the stall began, but before the failover timeout had elapsed). For example, if a physical standby database was in the APPLY-OFF state, it will remain in the APPLY-OFF state. The word manual is used to contrast this type of failover with a fast-start failover (described in Fast-Start Failover). This support note is available at http://support.oracle.com. the service configuration. MASTEROBSERVERHOSTS, DGMGRL reports an error if the 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. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . For more information, see START OBSERVER IN BACKGROUND. If there is more than one registered observer, then this command returns an error; a name is required if there is more than one observer. Valid values are >= 10. The ObserverOverride configuration property, when set to TRUE, allows an automatic failover to occur when the observer has lost connectivity to the primary, even if the standby has a healthy connection to the primary. Before beginning a failover, first determine that there is no possibility of recovering the primary database in a timely manner, and ensure that the primary database is shut down. To start an observer as a background process, use the DGMGRL primary database. Be aware that if you issue the following manual commands on either of those databases, then both the SALESRO and SALESRW services would be started on the databases regardless of what you may have earlier specified with the SRVCTL -role qualifier. The procedure for using RMAN to create a standby database is fully explained in Appendix F of Oracle Oracle Data Guard Concepts and Administration document (10g Rel 2 and 11g Rel 1). If the primary database has multiple standby databases, then you can specify multiple fast-start failover targets, using the FastStartFailoverTarget property. Figure 6-2 shows the observer monitoring a fast-start failover configuration. In order to maintain separation of Broker and non-Broker activity, a second static service is recommended. 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. The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. Check the Undo tablespace Usage in Oracle, Exclude/Include option in EXPDP and IMPDP Datapump, Missing Dependencies Python Core / win32api, Stop the EXPDP/IMPDP Datapump Job in Oracle, Find the temp usage by sessions in Oracle, Create & grant permission to directory in Oracle, Check the Patch Applied to the Oracle Database. Automatic failover is optional and can be enabled or disabled on your Autonomous Container Databases with Autonomous Data Guard. Apply services on all other bystander standby databases automatically begin applying redo data received from the new primary database. If there is only one registered observer, then it works in the same manner that a single observer worked prior to the advent of multiple observers in Oracle Database 12c Release 2 (12.2.0.1). When you select a standby database to be the next primary database after a switchover or a failover, there are several factors to consider. 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. If the observer is stopped abnormally (for example, by typing CTRL/C), restart it and reference the existing fsfo.dat file with the FILE IS qualifier. When both databases have been restarted, you may restart the observer. It automatically recovers the maximum amount of redo data for the protection mode the configuration is operating in. The Appendix provides information oncreating a simple wrapper script to start the observer as a background process. directory does not have the required permissions. How to Re-create and Reenable a Disabled Database. 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. In the event of a The following example shows you how to set up more than one service on a database and how using the broker ensures that the correct service starts on the correct database. START OBSERVING [cfg_group_name] starts a new observer for each broker configuration in the specified group. gets enabled and then begins monitoring. The original primary database will be restarted as a part of the switchover operation. Without the credentials, Broker will complete the role transition, but will leave the databases in need of a manual restart. 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. It uses the connect identifier specified in the observer configuration file to locate the credentials for a broker configuration from the Oracle wallet. To help you select an appropriate switchover or failover target, use the following DGMGRL commands which perform checks on the database to determine its readiness to complete a role change. Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. Client-side broker This results in the observer establishing a new connection to the primary database every 30 seconds. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. In these sample commands, the ellipse () signifies any other add service options you wish to supply. A running observer will follow the primary automatically after a role transition, but a newly (re)started observer won't start if the initial connection is to a down database or one with an out of date or corrupted Broker config file. If these parameters are modified outside of Broker, it raises a warning. The broker will not allow a switchover to a standby that has an apply delay configured (DelayMins property is set to a non-zero value). observer as a foreground process. 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. For example: You can find information about the master observer by querying the V$DATABASE view. If you do not want to use the default, you can define a specific group. The observer is the third party in an otherwise typical primary/standby Data Guard configuration. Displays when the target standby database does not have all of the primary database redo data and the configuration is operating in maximum availability mode. SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. Use the callout configuration file and script 1. Click Disable in the Fast-Start Failover wizard. the observer configuration file is observer.ora. The selected standby database that will be the fast-start failover target must receive redo directly from the primary database. the observer on ob2-host to become the master Credentials Required for Access to Broker Configurations. If you are performing an immediate failover, then the database role is changed to primary without applying any accumulated redo data. Initiate the failover on the standby database STAN: Services that must be active in any given database role (primary, physical standby, logical standby, or snapshot standby) must be configured with the Server Control utility (SRVCTL) explicitly on each database where the service must be active. Permissions Required by the DG_ADMIN Directory. Instead, Oracle Clusterware opens PDBs on particular instances based on Note that a switchover operation may be started before the specified wait It may be possible to convert the old Primary into a Standby database now instead of having to do a time consuming duplicate again. MASTEROBSERHOST TO command. Installing and starting an observer is an integral part of using fast-start failover and is described in detail in the following sections: Oracle Data Guard Installation explains that you can either install only the Oracle Client Administrator or you can install the complete Oracle Database Enterprise Edition or Personal Edition on the observer system. The target standby database when it does not have connectivity with the primary database, fast-start failover is disabled only on the target standby database. To maintain a viable disaster-recovery solution in the event of another disaster, you may need to perform additional steps. observer computer is returned to you so that you can continue to Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. The primary database must be running in order to start the observer. Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. Specifying the Observer Configuration File. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. 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. It will also alert you to databases that have had Flashback Database disabled at some point after FSFO was enabled. FAN server-side callouts can be configured on the database tier. to set the time taken to detect a failure on the primary database: Set the FastStartFailoverThreshold See "Database Service Configuration Requirements" for additional information about how the broker interacts with Oracle Restart. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). Fast-Start Failover allows Data Guard to automatically failover to a previously chosen standby database without requiring manual intervention to invoke the failover. If only a file name is Step:5Bounce your database and verify database name its open mode and its role. Steps to Create a Physical Standby Databa se 3 -3 Preparing the Primary Database 3 -4 FORCE LOGGING . Data Guard broker does not manage or store credentials. ObserverPingRetry properties before environment variable is set and the specified directory has the See Setting the Protection Mode for Your Configuration. This configuration property causes the former primary database to be automatically reinstated if a fast-start failover was initiated because the primary database was either isolated or had crashed. You can disable fast-start failover if necessary, by using the FORCE option. Reinstatement will have to be accomplished by other means (manual or scripted Broker commands). Subdirectories within required permissions, fast-start failover callouts will fail. JAVA applications can use FAN programmatically by using the JDBC FAN application programming interface to subscribe to FAN events and to execute event handling actions upon the receipt of an event. The reduced need for manual intervention can increase availability without increasing management costs. 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. The Oracle Database 11g observer can make use of specific credentials, allowing the same wallet to be used for multiple observers with different SYS passwords. This database property is used to specify how the observer should connect to and monitor the primary and standby database. To reenable broker management of these databases, you must reinstate or re-create the databases using one of the following procedures: If a database can be reinstated, the database will show the following status: Reinstate the database using the DGMGRL REINSTATE DATABASE command or the reinstate option in Cloud Control, as described in How to Reinstate a Database. Reinstatement of the failed primary database as a new standby database failed. Determines whether or not any standby databases that did not participate in the failover operation have applied redo data beyond the new primary database, and thus need to be disabled. 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 Immediate Failovers in Configurations Using Cascaded Standbys. primary. 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.
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