data guard failover steps data guard failover steps

fast-start failover through Cloud Control. A failover to a physical standby database is preferable because 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. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. CONNECT command. See the START OBSERVER command for more information. Now let's test switchover in the other direction. SQL> Select Database_role from v$Database; Hi, I am working in IT industry with having more than 10 year of experience, worked as an Oracle DBA with a Company and handling different databases like Oracle, SQL Server , DB2 etc In this mode, the FastStartFailoverLagLimit configuration property is set to a non-zero value. Switches roles between the primary and standby databases. In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. configuration file exists. DG BrokerDG BrokerData Guard BrokerOracleDGRMAN Duplicate . This list describes how the overall Oracle Data Guard protection mode is handled after a manual failover (complete or immediate). Oracle Data Guard Command-Line Interface Reference for more information about these broker commands. The playground: The general approach seems to be CDB level failover to standby , so the failover takes place at CDB to CDB , in an event where a single PDB is experiencing an issue , we will have to failover the whole instance ..this will impact all PDB's on the CDB. In this case, only observers on ob1-host and The default group is all the configurations defined in the observer configuration file. $DG_ADMIN directory. Queries and DML will continue to run - only sessions that commit will block. PDBs. Required fields are marked *. In the media recovery phase, Flashback Database applies redo to bring the database up to the standby_became_primary_scn. occur. Switchover Steps. 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. It must appear as the first part of an observer configuration file. WAIT option, broker waits for the amount of the observer configuration file is observer.ora. 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. committing because a fast-start failover may have occurred while it was In an Oracle Data Guard configuration, the SRVCTL -startoption and -role are updated after switchover to reflect the current open mode and database role on the new primary and standby databases. directory by this environment variable does not exist, or the $DG_ADMIN callout directory. To verify this change, again query the Database_role column of V$DATABASE. broker configuration, you must connect through another DGMGRL client You must specify it every time you start a new DGMGRL client. The service can be started on the physical standby only after the redo generated by starting the service has been applied. instructions for the DGMGRL command-line interface. 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. For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. Being FSFO ready means that all conditions are met for a successful failover, including having a running observer and sufficient redo transmitted to the failover target to meet durability requirements. operation. Indexing is a mechanism by which the underlying data is mapped for faster retrieval. observer. 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. FSFO enabled configurations having multiple standbys cannot switchover to a standby that is not the failover target. FSFO can provide substantial gains in high availability and disaster recovery preparedness for all environments, from inexpensive Cloud-based systems to global distributed data centers. If both HVR and Data Guard were running without latency or if no changes were made to the source database at the time of the failover, it can be assumed that all databases are synced and the no extra steps are necessary; the steps for Graceful Failover can be followed. Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. For reliable startup, the initial connection should always be made to the primary. After FSFO is enabled, Broker will continue to check that Flashback Database is enabled during health checks. FastStartFailoverLagLimit property. If the switchover occurs to a physical standby database, and the former primary (as it might in maximum availability and maximum performance modes). computer, it automatically starts the observer when you enable The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. A snapshot standby cannot be the target of a switchover or fast-start failover operation. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. 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. 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. directory has the same permissions as its parent directory. The time interval starts when the observer first loses its connection to the primary database. 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. If any errors occur during either conversion, the broker stops the switchover. file also declares broker configurations and defines configuration This is cleared on both when the reinstatement has been completed. It is very much useful, when the organization has multiple standby sites. Issue the following SRVCTL commands so that both databases in the Data Guard configuration know about the two potential services for each database: To start things up initially, you must manually start the services on the right node. Thus, the command-line prompt on the observer computer does not If this You can disable fast-start failover if necessary, by using the FORCE option. In a Managed Instance with multiple databases in Azure we can have high availability. It will not be allowed to open in any event if fast-start failover is enabled. name of the observer log file is Oracle 12c-Step by Step Manual Data Guard Failover. same permissions. When you select a standby database to be the next primary database after a switchover or a failover, there are several factors to consider. 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). Issue the DISABLE FAST_START FAILOVER command or the DISABLE FAST_START FAILOVER FORCE command. You have done a failover to your Standby database so it becomes the new Primary. change tracking enabled, broker enables block change tracking on the new *PATCH v5 0/6] Add Toshiba Visconti Video Input Interface driver @ 2023-01-11 2:24 Yuji Ishikawa 2023-01-11 2:24 ` [PATCH v5 1/6] dt-bindings: media: platform: visconti: Add Toshiba Visconti Video Input Interface bindings Yuji Ishikawa ` (5 more replies) 0 siblings, 6 replies; 42+ messages in thread From: Yuji Ishikawa @ 2023-01-11 . STOP OBSERVING, and SET 12c upgrade, The below commands will help to bring up standby as primary, https://www.linkedin.com/in/hari-prasath-aa65bb19/, https://www.facebook.com/groups/894402327369506/. On the Oracle Data Guard Overview page, click Database must be reinstated. The default value is 30 seconds. Broker is a Data Guard management utility that maintains state information about a primary and its standby databases. When you execute commands that affect multiple observers, if you have not specified a name and location for the observer configuration file, then broker searches the current working directory for a file named observer.ora. Oracle Data Guard Concepts and Administration provides information about setting up the databases in preparation of a switchover. The ObserverReconnect configuration property specifies how often the observer establishes a new connection to the primary database. 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 primary database can be reinstated if it had flashback database enabled. An observer is a separate OCI client-side component that run on a different computer from the primary and standby databases and monitors the availability of the primary database. If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. DGMGRL can be used to manage multiple observers in a group of broker configurations. It provides a way to quickly restore a database to a previous point in time or SCN using on-disk data structures called flashback logs. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. 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. The v$database view has has columns specifically for monitoring FSFO status. For example, if the limit specified is 30 seconds (the default), FSFO guarantees that all transactions that committed prior to 30 seconds ago are preserved during failover. Many customers use Oracle Database deployed on Amazon Elastic Compute Cloud (Amazon EC2) to run their Oracle E-Business Suite applications. Currently, this state can be detected only when the database is open. Since a fast-start failover (automatic failover) could become a false failover when the observer or the standby database cannot connect to the primary database within a specific time, which may cost the database to lose some transactions followed by reinstating or recreating the standby database (the former primary database). specified by the ObserverPingInterval property. 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. It also requires Flashback Database to be enabled on both the primary and target standby databases. irrespective of its content, indicates that the script executed successfully. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. To maintain a viable disaster-recovery solution in the event of another disaster, you may need to perform additional steps. The previous examples dealt with setting up only one service on a database. It will return PHYSICAL STANDBY, See the START OBSERVER This is true regardless of the settings for the FastStartFailoverPmyShutdown and FastStartFailoverAutoReinstate configuration properties. Verifies that the primary and the target standby databases are in the following states: The primary database is enabled and is in the TRANSPORT-ON state. If groups are not defined, you can still operate on all configurations defined in the file as a whole. The information in this guide is based on practical experience gained from deploying FSFO in a global corporate production environment. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. observer computer is returned to you so that you can continue to These required permissions, DGMGRL reports an error. observer on ob1-host will be given priority over Instead, it allows an observer that is monitoring the configuration to initiate a fast-start failover should database conditions warrant a failover. Flashing back a database is much faster and more seamless (one simple DDL statement) than traditional point-in-time or SCN-based recovery. In case of worst situation with data guard primary database, or not available for production than we can activated standby database as a primary production database. This may result in data loss. Observers continuously monitor the fast-start failover environment to ensure the primary database is available (described in When Fast-Start Failover Is Enabled and the Observer Is Running). configuration property. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL. Disabling Fast-Start Failover Using Cloud Control. If the switchover transitions a logical standby database to the primary role, then: The original primary database will be switched to a logical standby role. 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. If that metadata is pushed out, Oracle can no longer find a fuzzy snapshot so it will not be able to flash back. database's redo generation point by more than the value specified by the Set both these properties to achieve a primary failure detection time of 1 ObserverPingRetry configuration properties. The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. It could optionally also be removed from the primary database if there is no intention to ever run this service on the current primary database. disable fast-start failover with the FORCE option on the See "Database Service Configuration Requirements" for additional information about how the broker interacts with Oracle Restart. Oracle Database 10g allows a different password file to be used as long as the SYS passwords are the same on the primary and standby. This is particularly useful when registering with multiple listeners where the parameter value would otherwise exceed the 255 character limit. Otherwise, the DUPLICATE TARGET DATABASE command will fail with "RMAN-20208: UNTIL CHANGE is before RESETLOGS change". Therefore, the target standby never falls behind the primary Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. create the directory specified by the DG_ADMIN environment variable and Use the oraenv script provided by Oracle. Note that a switchover operation may be started before the specified wait However, re-enabling Flashback Database will require a bounce since the database must be mounted and not open. Only two databases, the primary and the failover target, can be in the FSFO configuration at any given time. If fast-start failover is initiated, the master observer verifies the target standby database is ready to fail over to the primary database role. Improper Oracle Net configuration is a leading cause of reported FSFO issues. The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. Databases that have been disabled after a role transition are not removed from the broker configuration, but they are no longer managed by the broker. fast-start failover to the target standby database if conditions warrant a failover. Nothing will ruin your day faster than finding out that the standby the observer just failed over to is 12 hours behind in applying redo. If fast-start failover is already enabled, the The failed primary database requires reinstatement as a new standby database to the new primary. The following sections describe how to reinstate or reenable a database. about starting the observer as a background Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. Always try to perform a complete failover first unless redo apply has stopped at the failover target due to an ORA-752 or ORA-600 [3020] error. If it reconnects to the primary database before the standby agrees to fail over, then the master observer will stop attempting to initiate a fast-start failover. The Appendix provides information oncreating a simple wrapper script to start the observer as a background process. Make sure that your OS environment on the standby is setup. ob2-host can be a master observer when 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. operation: Example 6-1 Fast-start Failover Configuration However failing over to a snapshot standby database will require more time because the broker must first convert it back to a physical standby database. The configuration must be operating in either maximum availability mode or maximum performance mode in order to be able to switch over to a logical standby database. Contains the observer log file for the broker configuration named 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. SHOW CONFIGURATION VERBOSE, or SHOW OBSERVER physical standby database. OBSERVER command, if this directory does not have the To achieve On the Data Guard Failover Confirmation page, specify the type of failover that you want to perform: Complete: All available redo is applied on the standby database. 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. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . In an Oracle Data Guard configuration, the SRVCTL -startoption for a standby database is always set to OPEN after a switchover. Choosing a Target Standby Database for Switchover and Choosing a Target Standby Database for Failover provide guidelines to help you choose a target standby database.