data guard failover steps

When using DGMGRL, you need to issue the SWITCHOVER command, specifying the name of the standby database that you want to change into the primary role. Conditions shown in blue are enabled by default. Oracle Data Guard Broker is a utility that can help you manage your Oracle Data Guard. In this case fast-start failover cannot occur because the databases are not ready to failover. Each database in a Data Guard configuration must have a unique name. SET ObserverConfigFile used to specify a customized observer configuration file. In An alternative is to enable flashback database on the primary (and the standby if desired) so in the event of a failover, the primary can be flashed back to the time before the failover and quickly converted to a standby database. 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. 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. Note that if the V$DATABASE.FS_FAILOVER_STATUS column has a value of DISABLED, then any values returned for the remaining columns related to fast-start failover (V$DATABASE.FS_FAILOVER_*) become irrelevant. Note the primary and target standby must have connectivity for this command to complete successfully. Subdirectories within When you are experiencing network disconnections and you issue the DISABLE FAST_START FAILOVER FORCE command on the primary database or a standby database that does not have connectivity with the primary database, fast-start failover may not be disabled for all databases in the broker configuration. A trigger on the DB_ROLE_CHANGE system event can be used to update the naming service and, with the proper client cache TTL settings, clients can connect to the new primary very quickly. Depending on the failover and the types of standby databases involved, some of the databases may need to be reinstated or re-created. You can manage observers through either the Oracle Data Guard Overview pages in Cloud Control or using DGMGRL commands. Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). This can be avoided by first disabling fast-start failover with the FORCE option on the target standby. A manual failover is already in progress. Any apply delay must be removed before beginning a switchover. Sign in to Azure If you will be using RMAN to create the standby database, it also needs a static service to restart the database being created. Default value is 100 You must also start and stop the SALESRO service on the primary so that it can be started on the standby. How we create a failover group in Azure Managed Instance For manual failover, the observer is started and communicating with the target standby database. Note: You can also use TNS aliases defined in the tnsnames.ora file when setting the local_listener parameter. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). 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. A switch-over allows the primary database to switch roles with its standby database. 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. Your email address will not be published. The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. This page will not allow you to alter the protection mode. Another good test is to simulate network failures that leave the primary up, but isolated from the failover target standby and the observer. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. To avoid problems due to timing variations, values less than 60 minutes are not recommended and values of 30 or less virtually guarantee Flashback Database failure. Overview of Switchover and Failover in a Broker Environment. It uses the connect identifier specified in the observer configuration file to locate the credentials for a broker configuration from the Oracle wallet. If any errors occur during either conversion, the broker stops the switchover. $DG_ADMIN/config_ConfigurationSimpleName/callout Application calls to DBMS_DG.INITIATE_FS_FAILOVER. times that the observer retries a failed ping before it initiates a by the current operating system user who is running DGMGRL The subdirectories Regards, Narottam Tagged: dataguard dba rac Welcome! Data Guard Failover to physical standby Tips - dba-oracle.com The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. The drain_timeout is specified in the SRVCTL In order to accommodate all load conditions, Oracle recommends having at least one more SRL group than the number of ORL groups of the same size. This means that in order for a flashback database operation to succeed, observer and the standby both lose contact with the primary. In addition, the primary database will shut down if it perceives a loss of connectivity for a period longer than FastStartFailoverThreshold seconds, if the FastStartFailoverPmyShutdown configuration property is set to TRUE. once the target standby database's redo applied point is no longer lagging behind the primary Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. STANDBY>ALTER DATABASE OPEN; However, re-enabling Flashback Database will require a bounce since the database must be mounted and not open. callout directory. The observer is perfectly satisfied if all of the redo it needs to meet your durability requirements has been received by the failover target. 3. See FastStartFailoverTarget for more information about this property. Aug 2022 - Present6 months. See the START OBSERVER The primary database was shut down without using the ABORT option. Reference architectures for Oracle databases on Azure - Azure Virtual SET MASTEROBSERVER TO allows you to manually change the observer configuration file. After a failover, the broker publishes Fast Application Notification (FAN) events. Open another prompt and connect to SQLPLUS: You cannot create the standby DB system in a different AD from the primary DB system. Setting this property to 'TRUE' (the default) causes the primary to self-terminate. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. A broker configuration can belong to multiple groups. When the conditions for fast-start failover are met, the Broker adds messages to the observer log and broker log indicating that fast-start failover would have been initiated. To start an immediate failover, use the DGMGRL FAILOVER TO database-name IMMEDIATE command. Configure the protection mode. 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. 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. Event notification and database connection failover support is available to database clients connected to local database services when a broker-managed failover occurs. instructions for the DGMGRL command-line interface. They must be re-created before they can serve as standby to the new primary database. 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. the SYSDG or SYSDBA privilege. Maximum Availability mode uses synchronous redo transfer and FSFO imposes the additional requirement that the redo is recorded in the standby redo log (SRL) of the target standby (AFFIRM option of log_archive_dest_ n). In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). 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. The Data Guard broker and the secondary database both run the observer and observe the primary database for downtime. However, fast-start failover cannot occur when the target standby database is in an unobserved state. fsfo_postcallout are stored in the same location as 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. This can be compared to performing an RMAN restore of the datafiles from a backup taken prior to the specified SCN, but is much faster. PRIM> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN; Fast-Start Failover in Data Guard Environments on Oracle Cloud If possible, confirm that fast-start failover has not FastStart Failover Ensues: Disaster strikes the primary database and its network connections to both the observer and the target standby database are lost. Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database: . To perform specified actions before or after a fast-start failover Indexing is a mechanism by which the underlying data is mapped for faster retrieval. This list describes restrictions when fast-start failover is enabled. are configured correctly. Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database. 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. (Yes, bystanders need Flashback Database too). Change Standby to Primary Database. If only a file name is If a failure occurs once a reinstatement operation (automatic or manual) is underway, the broker logs the appropriate information in the broker configuration files and broker log files. Do not use Shared Server (formerly MTS) for Data Guard. Slightly less critical than making sure you've got a good primary is making sure the failed primary can be automatically reinstated. The following paragraphs describe the supported availability modes. If the observer is unable to regain a connection to the primary database within the specified time, then the observer begins a fast-start failover provided the standby database is ready to fail over. In case of primary database failure, you will need to perform failover to transition the standby database to the primary role. To optimize the log apply rate: Do not configure the DelayMins database property to delay applying archived redo log files to the standby database (see Managing Log Apply Services for more information). Starting Observers as Background Processes. Guide to Oracle Data Guard Fast-Start Failover Steps for FAILOVER the Dataguard environment 1. When you configure data guard using OCI console, the default mode is set to maxprotection. Oracle Data Guard Concepts and Administration provides information about setting up the databases in preparation of a switchover. property. See theFlashback Database section above for information on storage requirements. 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. In the event of a Managed recovery process has been stopped between primary and standby database and standby becomes primary database. fast-start failover through Cloud Control. The remaining observers are called backup observers. A failover to a logical standby database requires that all physical and snapshot standby databases be re-created from a copy of the new primary database after the failover completes. 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. Create a pre-callout script, or a post-callout script, or both. The following paragraphs describe the supported availability modes. the current working directory, Uses standard output for displaying the observer logs. The default value is 30 seconds. If clients are already configured to automatically time out and reconnect if they don't get a response from the database, a simple but effective approach is to use a network alias (e.g. If 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. 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. With a value of TRUE for this property, the primary will shut down after being stalled for the number of seconds specified by the FastStartFailoverThreshold property. You want to conduct a manual failover to any standby database in the configuration (for example, because a failure occurred on the primary database at a time when the primary and target standby database were not ready to failover). Fast-start failover can be used only in a broker configuration and can be configured only through DGMGRL or Cloud Control. If the designated fast-start failover target develops a problem and cannot be the target of a failover, then the broker automatically changes the fast-start failover target to one of the other candidate targets. Verify the standby database instance is mounted. For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. Enabling fast-start failover and starting an observer process involves the following tasks. directory. this script is run before the fast-start failover is initiated. It shuts down or stalls because it is likely a failover has occurred. How to Re-create and Reenable a Disabled Database. 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; 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. If the primary is unable to contact the standby after a user specified period of time (NET_TIMEOUT option of log_archive_dest_ n), it drops out of synchronous transfer mode and begins operating as though it were in Maximum Performance mode. Disaster Recovery with Oracle Data Guard - online presentation The current primary database must have its LogXptMode property set accordingly and must have standby redo logs configured. You have done a failover to your Standby database so it becomes the new Primary. Download Ebook Oracle 11g 12c Data Guard With Asm Lab Practice A Complete Hands On Lab Practice To Manage A Data Guard . For example: The default value for the FastStartFailoverThreshold property is 30 seconds and the lowest possible value is 6 seconds. You will then need to re-create the physical standby databases from a copy of the new primary database before you can reenable them. After the conversion, the broker will start Redo Apply to apply accumulated redo data, before failing the database over to the primary role. 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. Note: Many of the Broker database properties correspond to database spfile parameters. It is then configured to be active in the PHYSICAL_STANDBY role on the physical standby database SOUTH. These are the actions the broker performs after you start a complete failover. This function can be called from a connection to either the primary or any standby in the configuration. restart the new physical standby database. FastStartFailoverLagLimit property. A fast-start failover to the target standby database fails. RAM). Oracle Database 10g databases running versions prior to 10.2.0.4 will remain in a stalled state until aborted or signaled to remain the primary by the observer once connectivity has been restored. 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". The target standby database is enabled and is in the APPLY-ON state. If the database is managed by Oracle Clusterware, broker does not open any pluggable When fast-start failover is enabled, the broker determines if a failover is necessary and initiates the failover to the current target standby database automatically, with no need for manual intervention. OBSERVE-ONLY: Fast-start failover is enabled in observe-only mode. If both the observer and designated standby database lose connectivity with the primary database for longer than the number of seconds specified by the FastStartFailoverThreshold configuration property, the observer will initiate a fast-start failover to the standby database. In this case, the observer cannot perform a fast-start failover even if conditions warrant a failover. Select name,open_mode,database_role from v$database; Step:2 Cancel the MRP process The word ALL cannot be used as a group name because it is a reserved keyword. The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. The string "NONAME" cannot be used as an observer name. Moorestown, New Jersey, United States. 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. The default value is ALL. 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. 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. configuration property. Before enabling fast-start failover, use one of the following techniques specified, the file is stored in an appropriate directory under the broker's The broker selects a target standby based on the order they are specified in the property.



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