command on the observer computer: The observer is a continuously executing process that is Immediate Failovers in Configurations Using Far Sync Instances. 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. The DB_ROLE_CHANGE event will fire whenever a database is opened for the first time after a role transition. However, you do have the option of specifying a name and location for the observer configuration file. In this mode, the FastStartFailoverLagLimit configuration property is set to zero. 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). Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database. Bystander standby databases may be disabled by the broker during the failover, and they must be reinstated or re-created before they can serve as standby databases to the new primary database. cannot use a different name for this file. files are stored in subdirectories of the DG_ADMIN directory. The broker first converts the original primary database to run in the standby role. These LGWR is unable to write to any member of the log group because on an I/O error. The former primary database is disabled. Failovers become routine. In a Managed Instance with multiple databases in Azure we can have high availability. When you run commands that need access to the observer The minimum value is 100 milliseconds. Prepare the primary database in advance for its possible future role as a standby database in the context of the overall protection mode (see Managing Data Protection Modes). Broker maintains these parameters by issuing ALTER SYSTEM commands as appropriate during role transitions, database startup/shutdown, and other events. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. You cannot perform a switchover to a snapshot standby database unless you first convert it back to a physical standby database. Starting Observers as Background Processes. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. Oracle 12c-Step by Step Manual Data Guard Failover. Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. The services include switchover, switchback and failover. The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database. The default name of the observer runtime data file is The primary database, it attempts to disable fast-start failover on as many databases in the configuration with which it has a network connection. Monitor the environment to ensure the primary database is available. Create a script to automate FSFO failover initiation and use it as your standard method for standby flips. This is normal. Note that the broker does not use the properties to set up redo transport services and Redo Apply services until you actually switch over the primary database to the standby role. The example uses the FROM ACTIVE DATABASE clause introduced in 11g that allows RMAN to create a standby database by copying the primary across the network without the need to store the backup files on disk or tape. To configure fast-start failover in observe-only mode: Fast-start failover will not be triggered if the primary or standby database is shut down normally. If this operation is successful, a zero data loss failover may be possible even if the primary database is not in a zero data loss protection mode. Administration at the target standby site should be as comprehensive as that at the primary site because the standby database may assume the primary role without prior notice. 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. There can be up to four Configure Data Guard Broker to manage and monitor the Data Guard configuration. Before stopping an observer, note the following: The observer does not stop immediately when you issue the STOP OBSERVER command. This Busca trabajos relacionados con New sql server failover cluster installation greyed out o contrata en el mercado de freelancing ms grande del mundo con ms de 22m de trabajos. You can switch back to the original Primary database later by performing another switch over. Oracle 19c-Step by Step Manual Data Guard Failover The group of broker configurations to be managed is declared in the observer configuration file. Oracle Data Guard 11gR2 Administration : Beginner's Guide Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by select name,open_mode,database_role from v$database; Note: Be aware that if you issue the following manual commands on either of those databases, then both the SALESRO and SALESRW services would be started on the databases regardless of what you may have earlier specified with the SRVCTL -role qualifier. This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. The word manual is used to contrast this type of failover with a fast-start failover (described in Fast-Start Failover). Steps for Data guard Switch-over and Switchback in Oracle - Doyensys If you don't already have a Flash Recovery Area (FRA), you will need to create one for Flashback Database. Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database: . Set this property for the primary and target standby database if you want the observer to use a different connect identifier than that used to ship redo data (that is, the connect identifier specified by the DGConnectIdentifier property). The v$database view has has columns specifically for monitoring FSFO status. SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. On the Oracle Data Guard Overview page, click Database must be reinstated. The subdirectories that DGMGRL creates under this directory will also have the 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. observer and the others are backup observers. The target standby database has contact with the primary database. If the value is non-zero, failover is possible any time the standby database's apply If the DG_ADMIN environment variable is not set, or the Once the observer is started, you cannot change the file's name and location. Moorestown, New Jersey, United States. 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. Reinstatement will have to be accomplished by other means (manual or scripted Broker commands). time specified in the WAIT option. In an environment where there are multiple observers configured, stopping the master observer is not allowed unless it is the last running observer. Running a StatusReport on the primary should verify that the error is due to a missing observer. 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. 3. 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 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. Note: this state also occurs on the primary during startup when fast-start failover is possible and neither the target standby database nor the observer are present to confirm it is okay to continue opening the database. In such cases, the failed primary database is reinstated as a physical standby database. In this example, the original primary data is called PRIM and the original standby database is called STAN. Figure 6-1 Relationship of Primary and Standby Databases and the Observer. See Oracle Enterprise Manager Command Line Interface. Do not use Shared Server (formerly MTS) for Data Guard. Tags: Data Guard, Oracle. The SHOW CONFIGURATION command will show you which databases can be reinstated and which databases must be re-created. The FORCE option may be the preferred method for disabling ConfigurationSimpleName represents How to switch roles in Oracle Data Guard - The Geek Diary OBSERVER command, if this directory does not have the 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 following sections describe how to perform manual failovers: Reenabling Disabled Databases After a Role Change. The name of the callout configuration file is fsfocallout.ora. Therefore, the target standby never falls behind the primary In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. value of the FastStartFailoverThreshold property. A single-instance database must be registered with Oracle Restart in order to publish FAN events via ONS. Follow the guidelines described in Choosing a Target Standby Database. See FastStartFailoverTarget for more information about this property. It automatically sets Data Guard related database initialization parameters on instance start and role transitions, starts apply services for standbys, and automates many of the administrative tasks associated with maintaining a Data Guard configuration. If you are more concerned about the performance of the primary database than a minimal loss of data, consider enabling fast-start failover when the configuration protection mode is set to maximum performance. If Flashback Database fails, automatic reinstatement stops and you will have to perform a manual SCN-based recovery to the standby_became_primary_scn and complete the reinstatement. We'll leave the other properties at their default values for the walkthrough, but you should become familiar with all of the Broker config and database properties. Databases that can be reinstated will have the following status value: For the REINSTATE command to succeed, Flashback Database must have Note: the FSFO observer version must match the database version. Data guard Configuration details:- Login in to Standby Server:- Step:1 Check the database role and open_mode Select name,open_mode,database_role from v$database; This lets you take advantage of the broker's RMAN also copies the spfile and password files and you can change the values for individual parameters. In Maximum Availability mode, FSFO guarantees that no transaction that has received a commit acknowledgment will be lost during a failover. The configuration and database status report the same error messages as are returned when there is only one registered observer. Displays only on the target standby database when it is SYNCHRONIZED with or is TARGET UNDER LAG LIMIT of the primary database, has connectivity to the observer, but the primary database does not have a connection to the observer. This action will result in loss of data and the possibility of two databases in the configuration simultaneously assuming the primary database role. If you already have an FRA, you may need to increase its size in order to accommodate the Flashback Database files. In addition to setting the configuration protection mode to maximum performance, you will also need to ensure that the LogXptMode database property for both the primary and target standby database is set to ASYNC. You can optionally indicate the database health conditions that should cause fast-start failover to occur. As shown in the table, fast-start failover can be enabled in maximum availability Oracle Data Guard Command-Line Interface Reference for more information about these broker commands. To start an immediate failover, use the DGMGRL FAILOVER TO database-name IMMEDIATE command. Dataguard broker is used to automate monitoring and controlling standby setups. Then the STOP OBSERVER command can be issued successfully on the former master observer. We'll start with switchovers. 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. upheld. Step 4: Enable Fast-Start Failover Now we are ready to enable FSFO: DGMGRL> enable fast_start failover; Enabled in Zero Data Loss Mode. In case of primary database failure, you will need to perform failover to transition the standby database to the primary role. Is possible if the target standby database displays SYNCHRONIZED and the FS_FAILOVER_OBSERVER_PRESENT column displays YES. 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. A failed ping is a ping to The Appendix provides information oncreating a simple wrapper script to start the observer as a background process. You can manually stop a specific observer or all observers. to set the time taken to detect a failure on the primary database: Set the FastStartFailoverThreshold Ensure this file cannot be read by unauthorized users. What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. Chapter 9 of the Data Guard Broker documentation (10g and 11g) contains a description of each property. Oracle recommends configuring Flashback Database on every database so that if failover occurs to a physical standby database, you can more easily reinstate any disabled standby databases. Oracle Data Guard Broker is a utility that can help you manage your Oracle Data Guard. This document only talks about switchover involving physical standby database. Don't initiate failover unless at least 30 minutes of history is available. Whenever possible, you should switch over to a physical standby database: If the switchover transitions a physical standby database to the primary role, then: The original primary database will be switched to a physical standby role. 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. Broker can be configured to initiate failover on any of the following conditions. By default, a fast-start failover is done when both the observer and the standby cannot reach the primary after the configured time threshold (FastStartFailoverThreshold) has passed. Stopping the observer does not disable fast-start failover. 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. Step-B: Copy control file to temporary location on primary database. (Note that the target standby cannot be a far-sync instance. This support note is available at http://support.oracle.com. client-side broker files, the specified values are used. If the service has been configured to start automatically (-policy AUTOMATIC), then the service will automatically start only after a database role change. The FS_FAILOVER_STATUS column in the V$DATABASE view for the target standby database displays a reason why fast-start failover cannot occur. If the target is a snapshot standby database, the broker first converts the database back to a physical standby and then starts Redo Apply to apply all the accumulated redo before completing the failover and opening the database as a primary database. This list describes restrictions when fast-start failover is enabled. directory specified by this variable does not exist, or the directory does not have the Table 6-2 FS_FAILOVER_STATUS Column of the V$DATABASE View. Learn how to use Oracle Data Guard broker to manage databases during switchover and failover. Disabling fast-start failover does not stop the observer. A high lag limit may lead to more data loss but may lessen the performance impact of the primary database. 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. Broker stores it configuration information in a mirrored set of files outside the database. Improper Oracle Net configuration is a leading cause of reported FSFO issues. Example 6-2 Sample Observer Configuration File. DGMGRL. Install the DGMGRL command-line interface on the observer computer as described in Oracle Data Guard Installation. observers are registered, a directory named 8.2 Private Cloud Appliance and . If they are isolated from each other, then you must first disable fast-start failover by using the FORCE option, and then stop the observer. Some properties have changed between those releases. Create a pre-callout script, or a post-callout script, or both. 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. on particular instances based on the service configuration. (Oracle Call Interface) client that connects to the primary and target standby databases Cloud Control will start the observer. milliseconds and that of ObserverRetryCount is 10. Notice that the former primary is now disabled. Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. Fast-Start Failover in Data Guard Environments on Oracle Cloud 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. For example: The following example shows the fast-start failover information for the DRSolution configuration: The following SHOW OBSERVER command displays information about multiple observers in the DRSolution broker configuration. The FastStartFailoverLagLimit configuration property is only used by the broker when enabling fast-start failover for configurations operating in maximum performance mode. Oracle also provides Fast Application Notification (FAN) for OCI clients and Fast Connect Failover for JDBC clients. Now that we know switchovers work, it's time to test failovers. The broker controls the rest of the switchover. Such preparation includes: Ensuring that standby redo log files are configured on the primary database. If this occurs, run 'stop observer' and try again. FastStartFailoverLagLimit SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; For each broker configuration on which one or more services. See Directing a Fast-Start Failover From an Application). required permissions, the admin folder is created (This is useful because the name defined in the metadata may contain whitespace and international characters, which the observer configuration file does not allow.). At this point, you can either: Disable fast-start failover (described in Disabling Fast-Start Failover) and attempt to open the former primary database, Manually reinstate the former primary database, as described in Reenabling Disabled Databases After a Role Change. Use broker configuration properties to set the time taken to detect a You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. Use Broker's "show configuration" command to determine FSFO status and the "show database
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