A good method to determine Flashback Database storage requirements is to enable Flashback Database and observe the amount of storage it uses during several peak loads. A number of prerequisites must be met on the primary in order to use Fast-Start Failover. To change the FastStartFailoverTarget property to point to a different standby database, disable fast-start failover, set the FastStartFailoverTarget property, and reenable fast-start failover. The following sections provide more information about the fast-start failover environment: When Fast-Start Failover Is Enabled and the Observer Is Running, Restrictions When Fast-Start Failover is Enabled, Shutting Down the Primary Database When Fast-Start Failover Is Enabled, Performing Manual Role Changes When Fast-Start Failover Is Enabled. Start the Data Guard listener on both "a" and "b" hosts. 99 Software Similar To Oracle Data Guard Backup & Sync The following is an example of starting an observer as a background process: The START OBSERVER IN BACKGROUND command uses Oracle wallet to obtain credentials to log into the database server and register observers. The database on which the procedure is called notifies the observer. You want to prevent fast-start failover from occurring because the primary database will resume service soon. Immediate: No additional data is applied on the standby database, resulting in a data-loss . The observer configuration file is a text file and the syntax to define observers and groups is similar to that used in the listener.ora or tnsnames.ora files. Fast-start failover is enabled, but this standby database is not the target of the fast-start failover. database (if real-time query is enabled). Broker will set the primary to use asynchronous log transport by default. A far sync instance or Zero Data Loss Recovery Appliance is not a database and therefore cannot be the target of a role transition. Perform SWITCH LOGFILE if necessary. The If necessary, you can shut down the primary or target standby database in a fast-start failover environment. See Reenabling Disabled Databases After a Role Change for more information. Each group that you define must have at least one broker configuration. Download Ebook Oracle 11g 12c Data Guard With Asm Lab Practice A Using the db_unique_name of each database as the Oracle Net alias is simple and intuitive. On primary database NORTH, execute the following: On standby database SOUTH, execute the following: Services that are to be active while the database is in the physical standby role must also be created and started on the current primary database regardless of whether the service will be started on that database or not. Else, broker restarts the new (as it might in maximum availability and maximum performance modes). It is very much useful, when the organization has multiple standby sites. Your email address will not be published. Enabling fast-start failover does not trigger a failover. Then, on the Fast-Start Failover Change Mode page, click Enabled. If the observer finds that the database is no longer the primary, it will attempt to reinstate it as the failover target standby. pre-callout configuration script and post-callout configuration script. ORACLE-BASE - Data Guard Bounce your database and verify database name its open mode and its role: SQL> shutdown immediate; ORA-01109: database not open Database dismounted. Use the SHOW CONFIGURATION BystandersFollowRoleChange command to see the value of this property. Verify there are no active users connected to the databases. Make some new changes and verify that they are preserved after failover. 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. Overall Steps:-. For example: Scenario 6: Enabling Fast-Start Failover and Starting the Observer. You can enable fast-start failover from any site while connected to any database in the broker configuration. This property also affects whether the broker skips viability checks of bystander standby databases when a fast-start failover occurs. If the configuration contains both physical and logical standby databases, consider choosing a physical standby database (that has the least amount of unapplied redo) to be the target standby database. Verify the standby database instance is mounted. In an environment where there are multiple observers configured, stopping the master observer is not allowed unless it is the last running observer. crash, data in this file can be used to restart the observer to the The commands that can be executed for a group of configurations (as declared in an observer configuration file) are as follows. ConfigurationSimpleName represents This list contains some recommendations to obtain better performance when using fast-start failover. Then set the configuration protection mode to maximum availability. In addition, the database to be reinstated and the new Fast-start failover will not be attempted for the other types of database shutdown (NORMAL, IMMEDIATE, TRANSACTIONAL). Install the DGMGRL command-line interface on the observer computer as described in Oracle Data Guard Installation. Alternatively, you can query the V$DATABASE view on the target standby database. Note that if failover was performed on a snapshot standby database, the old primary must be either reinstated or re-created as a physical standby database. Flashback Database records the before-image of changed blocks. When querying the V$DATABASE view, pay special attention to the following: The FS_FAILOVER_STATUS column, which can contain the values described in Table 6-2. Input commands are shown in shaded boxes in normal text. If the failover target is a logical standby database, the original primary database and all physical and snapshot standby databases in the configuration will be disabled. The list is empty by default. The broker allows the failover to proceed as long as there are no errors for the standby database that you selected to participate in the failover. 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. Time for action - using interfaces to monitor Data Guard; Other replication solutions and Data Guard; This article - the seventh in this ongoing . The reduced need for manual intervention can increase availability without increasing management costs. alter database recover managed standby database finish; alter database activate standby database; Managed recovery process has been stopped between primary and standby database and standby becomes primary database. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. . If possible, confirm that fast-start failover has not callout directory. 4. As mentioned above, Maximum Availability mode is mandatory for Oracle Database 10g and optional for Oracle Database 11g. If only a path is specified, the files are If the database is not managed by Oracle Clusterware, directory has the same permissions as its parent directory. Then, click Continue to proceed to the next page. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . This specifies how often the observer establishes a new connection to the primary database. 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). 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. By default, the broker always determines whether bystander standby databases will be viable standby databases for the new primary when performing a complete failover. Oracle Data Guard Command-Line Interface Reference for more information about these broker commands. Remember to check Flashback Database history before aborting the primary. To specify which observer can be a master observer when a database is in Testing FSFO failover requires simulating loss of the primary. The standby can be physical or logical and there can be multiple standbys, but only one of the standbys can be the failover target at any given time. There can be up to four Just be sure to include a Flashback Database history check in the script to provide an option to abort if a failover would require a manual reinstate. The observer does not attempt to reinstate the former primary database. There are normally two situations when this operation will be performed: a planned outage for maintenance of the primary database or disaster recovery. If that metadata is pushed out, Oracle can no longer find a fuzzy snapshot so it will not be able to flash back. Standby databases not involved in the switchover (known as bystander standby databases) continue operating in the state they were in before the switchover occurred and will automatically begin applying redo data received from the new primary database. Logical standby databases that are disabled during failover can be reinstated. Currently, this state can be detected only when the database is open. This support note is available at http://support.oracle.com. 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. When you start a switchover, the broker verifies that at least one standby database, including the primary database that is about to be transitioned to the standby role, is configured to support the overall protection mode (maximum protection, maximum availability, or maximum performance) after the switchover is completed. If the configuration contains physical, snapshot, and logical standby databases, consider choosing a physical standby database as the target standby database. But it will also continue trying to reconnect to the primary database indefinitely. 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. All physical and snapshot standby databases will be disabled and must be re-created from a copy of the new primary database after a switchover to a logical standby database. These are some points to consider before you begin a switchover. /home1/dataguard/config_NorthSales/callout/fsfocallout.ora. Flashing back a database occurs in two stages: For FSFO environments, set db_flashback_retention_target = 60 or higher to provide sufficient Flashback Database history for automatic standby reinstatement. The word manual is used to contrast this type of failover with a fast-start failover (described in Fast-Start Failover). The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. 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. issue commands and interact with the broker configuration. Albino DeSantis - Senior System Engineer - US Coast Guard - LinkedIn You can switch over or manual failover to a bystander database. The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. time, if all the sessions that are connected though the active services Fast-start failover can incur data-loss within the time specified by FastStartFailoverlagLimit. Enable Fast-Start Failover Using Cloud Control. Notice that the former primary is now disabled. Use the EMCLI verb dg_configure_observers. configuration property specifies how frequently the observer Even if you have successfully connected to a database server in the broker configuration using the CONNECT command, this command ignores the existing connection and uses the credentials stored in Oracle wallet. 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. SET ObserverConfigFile used to specify a customized observer configuration file. They must be re-created from a copy of the new primary database. Data Guard Switchover/failover to standby The standby database will be activated to serve as the primary database at some point in its life cycle. You can also switch the master observer hosts for a group of configurations to one specific host. Set the, Configure the connect descriptor with a single network name that is registered with a global naming service such as DNS or LDAP. 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. Unlike the primary / standby interconnect, where bandwidth and latency are determining performance factors, the observer requires very little network bandwidth and is not overly latency sensitive, allowing the it to be placed practically anywhere a reliable connection is available. As described in theFlashback Database section, Flashback Database takes place in two stages: a restore stage and a media recovery stage. We want the observer to be able to automatically reinstate the former primary as a standby after our failover tests, so before each test, make sure that Flashback Database has at least 30 minutes of history. The broker first converts the original primary database to run in the standby role. If you intend to switch back to the original primary database relatively soon, you may allow the physical and snapshot standbys to remain disabled. The broker allows the switchover to proceed as long as there are no errors for the primary database and the standby database that you selected to participate in the switchover operation. A high lag limit may lead to more data loss but may lessen the performance impact of the primary database. This lets you take advantage of the broker's The remaining observers are called backup observers. You can also query the V$FS_FAILOVER_STATS view to display statistics about fast-start failover occurring on the system. While not strictly required, creating a wallet provides a secure way to store the credentials needed to automatically connect to the primary when starting the observer. The observer maintains state information in a file. present, you must start the observer manually using the following The ObserverReconnect configuration property specifies how often the observer establishes a new connection to the primary database. When both databases have been restarted, you may restart the observer. 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. Broker changes database parameters during startup and role transitions via ALTER SYSTEM commands. The following sections describe how to perform manual failovers: Reenabling Disabled Databases After a Role Change. If the target standby database is ready for failover, then the master observer immediately directs the target standby database to fail over to the primary database role. 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. (For example, if the DBMS_LOGSTDBY.SKIP procedure was used to specify which database operations done on the primary database will not be applied to the logical standby database.). After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. primary database must have network connectivity. The other configurations that are not required but they might make your fast-start failover go smoothly. What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. For switchovers, understanding all of the factors can simplify the choice of which standby database to consider as your new primary database. Oracle 12c-Step by Step Manual Data Guard Failover Initiate the failover on the standby database STAN: A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. When this command is issued, the actual property. If you do not want to use the default, you can define a specific group. WAIT option, broker waits for the amount of Presetting database properties related to redo transport services, such as LogXptMode, NetTimeout, StandbyArchiveLocation, StandbyAlternateLocation, and RedoRoutes. configuration named ConfigurationSimpleName. Complete Failovers in Configurations Using Far Sync Instances. file also declares broker configurations and defines configuration If a bystander standby database is not disabled by the broker during this failover, it will remain in the state it was in before the failover. (If there are other conditions, unique to an application, that would warrant a fast-start failover then the application can be set up to call the DBMS_DG.INITIATE_FS_FAILOVER function and start a fast-start failover immediately should any of those conditions occur. If local_listener is already in use, add the Data Guard listener to the list. Then the STOP OBSERVER command can be issued successfully on the former master observer. Fast-start failover can be used only in a broker configuration and can be configured only through DGMGRL or Cloud Control. the SYSDG or SYSDBA privilege. 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 immediate failover should only be performed when a complete failover is unsuccessful or in the error cases just noted. Goal. If you have not used the SET ObserverConfigFile command after starting the current DGMGRL client, then the result will always be: ObserverConfigFile=observer.ora. observer. 11.2 rac servicefailover 2020-01-28 ORACLE ORACLE RAC/ASM RAC112. Thus, the command-line prompt on the observer computer does not The following sections provide information about managing observers: How the Observer Maintains Fast-Start Failover Configuration Information, Patching an Environment When the Observer Is Running and Fast-start Failover Is Enabled. second. observers for a single Data Guard configuration. Before enabling fast-start failover, use one of the following techniques Regardless of the method you choose, the broker coordinates the role transition on all databases in the configuration. To failover, connect to the standby database and use the DGMGRL FAILOVER TO db-unique-name command. Immediate Failovers in Configurations Using Far Sync Instances. If the Clusterware: The broker notifies Oracle Clusterware to stop active In a separate terminal session, verify the configuration. Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. 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. It will not be allowed to open in any event if fast-start failover is enabled. configuration file, and fast-start failover callout script files. Only the master observer can coordinate fast-start failover with Data Guard broker. Getting the Oracle Net configuration right is one of the key factors in a successful FSFO deployment. See Manual Failover for information about manual failover. DG BrokerDG BrokerData Guard BrokerOracleDGRMAN Duplicate . See Oracle Enterprise Manager Command Line Interface. This can happen for either of the following reasons: A bystander standby database has applied more redo data than the new primary database itself had applied when it was a standby database. 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. 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. specified, the file is stored in an appropriate directory under the broker's For manual failover, the observer is started and communicating with the target standby database. callout configuration file. For this build, we will use a single physical standby database. 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 Oracle Data Guard configuration is operating in maximum protection mode, the broker does not allow a switchover to occur to a logical standby database. In 10g, a single wallet can be used for multiple observers, but they must all use the same SYS password. Disabling fast-start failover does not stop the observer. If the configured data loss guarantee cannot be upheld, Provides an automatic failover environment that Another good test is to simulate network failures that leave the primary up, but isolated from the failover target standby and the observer. Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database: . Switchover and Failover Operations - Oracle Help Center Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. Enabling fast-start failover in a configuration operating in maximum performance mode provides better overall performance on the primary database because redo data is sent asynchronously to the target standby database. observer and the others are backup observers. It is then started and stopped on the primary database. Reset database properties related to Redo Apply services, such as DelayMins. If there are many actions that need to take place, put them in a separate script and use the trigger to run the script in an orphan process or thread independent of the database. In the event of a Step-B: Copy control file to temporary location on primary database. 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 The example assumes that the standby uses the same directory structure as the primary. db1_a: Alias to connect to the dynamic Data Guard service on database "a", db1_b: Alias to connect to the dynamic Data Guard service on database "b", db1_a_static: Alias to connect to the static Data Guard service on database "a", db1_b_static: Alias to connect to the static Data Guard service on database "b". Steps that require the primary to be in a mounted (not open) state are grouped together in the section below entitled Steps Requiring a Bounce of the Primary. If the observer is unable to regain a connection to the primary database within the specified time, and the target standby database is ready for fast-start failover, then fast-start failover ensues. 3. If the protection mode was at maximum protection, it is reset to maximum performance. For any work, queries and help. list of the observers that can become the master observer when that configuration scripts and checks for errors or misconfigurations. For each temporary table, verifying that temporary files associated with that table on the primary database also exist on the standby database. Reinstate the original primary database to act as a standby database in the new configuration. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. After setting local_listener, register the database with the listener and verify the services have been registered. Data Guard Failover to physical standby Tips - dba-oracle.com The same process should work for RAC environment as my colleague has . Errors occurring for any other configuration members will not impede the switchover. Broker Configuration Has Only One Registered Observer. services. The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database.
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