failover to the target standby database. computer, it automatically starts the observer when you enable If the primary database is an Oracle Real Application Clusters (Oracle RAC) database, the master observer will attempt to connect to one of the remaining primary instances. Only the master observer can coordinate fast-start failover with Data Guard broker. DG_ADMIN environment variable is not set, the files are stored in command is submitted successfully, the command-line prompt on the You can also reinstate bystander standby databases that were disabled during a failover operation. A single-instance database must be registered with Oracle Restart in order to publish FAN events via ONS. Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring FAN, FCF, and ONS on an Oracle Real Application Clusters (Oracle RAC) database. To protect the files, it's good practice to store them in separate filesystems. 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. Tags: Data Guard, Oracle. SHOW OBSERVERS [FOR fg_group_name ] shows information about observers for all configurations in the specified group. Set the, Configure the connect descriptor with a single network name that is registered with a global naming service such as DNS or LDAP. To verify this change, again query the Database_role column of V$DATABASE. specified by the ObserverPingInterval property. SWITCHOVER command, and the databases are managed by Oracle 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). Oracle Database 11g FSFO adds support for Maximum Performance mode (async redo transfer), providing the flexibility to trade durability for performance. Data Guard Failover to physical standby Tips - dba-oracle.com Sets up redo transport from the new primary to the other members of the configuration, Starts Redo Apply services on the new standby, Ensures the other standbys in the broker configuration are viable to the new primary, Integrates with Oracle Clusterware and Oracle Global Data Services (GDS) to ensure that the proper services are started after a role change. 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. After a complete failover finishes, any bystander standby database that is not viable as a standby for the new primary database will be disabled by the broker. Reconnect within the time specified by the FastStartFailoverThreshold property. FastStartFailoverLagLimit property. 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. Once the primary database regains connectivity with the target standby database, fast-start failover will be disabled for all the databases in the configuration. If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. The observer immediately initiates a fast-start failover, as long as the failover target database is in a valid fast-start failover state ("observed" and either "synchronized" or "within lag") to accept a failover. These FAN events can be used in the following ways: Applications can use FAN without programmatic changes if they use one of these Oracle integrated database clients: Oracle Database JDBC, Oracle Database Oracle Call Interface (OCI), Oracle Data Provider for .NET ( ODP.NET), or Universal Connection Pool for Java. 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. Disabling Fast-Start Failover Using DGMGRL. Broker will set the primary to use asynchronous log transport by default. The act of switching roles should be a well-planned activity. As described in theFlashback Database section, Flashback Database takes place in two stages: a restore stage and a media recovery stage. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. By default, the broker always determines whether bystander standby databases will be viable standby databases for the new primary when performing a complete failover. Depending on the failover and the types of standby databases involved, some of the databases may need to be reinstated or re-created. This document describes how to setup clients to connect to Data Guard databases (primary and standby) and configure automatic client failover such that in case there is role change due to switchover or . You must use the Oracle wallet to store the credentials for all broker configurations to be managed. During a complete failover, the broker performs the failover steps described in How the Broker Performs a Complete Failover Operation. 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. Among many benefits of using this utility, I highlight that while using it, it will not need manual intervention to recover the databases or eventually a switchover in case the primary database becomes unavailable. 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. through these services to exit or for the specified wait time Required fields are marked *. If you are performing an immediate failover, then the database role is changed to primary without applying any accumulated redo data. Data Guard | Oracle Configure one or more active standby databases Minimize downtime for upgrades In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). Data Guard switchover with dgmgrl - dba-oracle.com 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. Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database. In a manual failover, you convert a standby database to a primary database because the original primary database failed and there is no possibility of recovering the primary database in a timely manner. environment that is guaranteed to either lose no data (when the REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. November 20, 2009. When a primary loses contact with both the failover target and the observer simultaneously, it enters a "stalled" state (v$database.fs_failover_status = 'STALLED') and any sessions still connected to the primary will block on commit. If this by the current operating system user who is running DGMGRL The subdirectories In this case fast-start failover cannot occur because the databases are not ready to failover. 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. Broker keeps its configuration details in flat file. 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. Enabling fast-start failover does not trigger a failover. broker opens all the PDBs on the new primary database and on the target standby It is then configured to be active in the PHYSICAL_STANDBY role on the physical standby database SOUTH. SHOW ObserverConfigFile used to check the runtime property ObserverConfigFile. The observe-only mode for fast-start failover enables you to test how fast-start failover will work in your environment. Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. This FastStartFailoverLagLimit property. fsfocallout.ora. Fast-Start Failover in Oracle 11g Data Guard. The target standby database is synchronized with the primary database if it is a configuration operating in maximum availability or maximum protection mode, or the target standby database is within the lag limit if it is a configuration operating in maximum performance mode. PRIM> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN; Permissions Required by the DG_ADMIN Directory. If it detects that Flashback Database was disabled, either manually, or automatically because Flashback Database discovered a problem, Broker signals "ORA-16827: Flashback Database is disabled". session. This post will demonstrate the procedure to test Oracle Data Guard Fast-Start Failover by shutting down the server where the primary database is running from. For more details about managing redo transport services using database properties, see Managing Redo Transport Services. 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. are configured correctly. environment variable to specify the default location for client-side broker files. Note that enabling FSFO does not make the configuration ready for automatic failover - that requires an observer, which we'll get to next. Data Guard Broker Failover - DBA Genesis Support Verify there are no active users connected to the databases. Initiate the failover on the standby database STAN: SQL>connect /@STAN as sysdba SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; 2. The observer automatically starts the reinstatement process. The failover was to a logical standby database. Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. Neither the primary database nor the logical standby database needs to be restarted after the switchover completes. In maximum protection mode, set the LogXptMode database property to SYNC (note that in maximum protection mode, a far sync instance cannot be used to ship redo to a standby). lower detection times for primary database failures, you must 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. Oracle recommends that this property be set to a value that is small enough to allow timely detection of faults at the primary database, but large enough to limit the overhead associated with periodic observer connections to an acceptable level. If the currently configured mode is maximum protection, Cloud Control will downgrade the mode to maximum availability. standby database, host, or network failure, etc.). performance protection mode with fast-start failover. For switchovers, understanding all of the factors can simplify the choice of which standby database to consider as your new primary 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. miliseconds. Use the wrapper script to start the observer process when the observer host boots or to restart it if it dies. To stop the observer when fast-start failover is disabled, the primary database must be running. 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. The ObserverPingInterval Verify the primary database instance is open. 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. You can perform a manual failover even if fast-start failover is enabled. usually within three seconds if fast-start failover is enabled. A switchover to a physical standby database is preferable because all databases in the configuration will be available as standby databases to the new primary database after the switchover operation completes. https://www.facebook.com/dbahariprasath/? There is no need to multiplex SRLs in order to protect redo as with ORLs (the redo is already protected in the ORLs of the primary). Learn how your comment data is processed. A switchover guarantees no data loss. configuration file 2. The SRVCTL utility does not automatically take the database role into account, so any time you start a service manually, you must specify the name(s) of the service you want started. Using the db_unique_name of each database as the Oracle Net alias is simple and intuitive. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. However, re-enabling Flashback Database will require a bounce since the database must be mounted and not open. ASYNC. The redo transport mode used to send redo to the target standby database or the database currently in the primary role. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. Flashback Database records the before-image of changed blocks. The default value is 30 seconds and the lowest possible value is 5 seconds. Issue the DISABLE FAST_START FAILOVER command or the DISABLE FAST_START FAILOVER FORCE command. Note that role changes to logical standby databases always result in physical standby database bystanders being disabled. 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. Data Guard Configuration Details:-. The required attributes vary depending on your configuration (including whether your environment is Oracle RAC-based or single-instance). They must be re-created from a copy of the new primary database. The real test of the configuration is a successful role transition in both directions with both switchover and FSFO failover. This file is stored in the STANDBY>ALTER DATABASE OPEN; WAIT option, broker waits for the amount of The following paragraphs describe the supported availability modes. LinkedIn:https://www.linkedin.com/in/hari-prasath-aa65bb19/ If you have not used the SET ObserverConfigFile command after starting the current DGMGRL client, then the result will always be: ObserverConfigFile=observer.ora. isolated. You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. Click Failover. Add the SRLs. They must be re-created before they can serve as standby to the new primary database. create the directory specified by the DG_ADMIN environment variable and The 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. Tailing the alert logs on the primary and standby is a good way to watch Broker in action and get familiar with how it performs various tasks. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. Displays if the standby database's redo applied point does not lag the primary database's redo generation point by more than the number of seconds specified by the FastStartFailoverLagLimit configuration property and the configuration is operating in maximum performance mode. If you will be using RMAN to create the standby database, it also needs a static service to restart the database being created. 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. When this property is set to the default value of 0, it prevents the observer from periodically establishing a new connection with the primary database. The primary database was shut down without using the ABORT option. Some properties have changed between those releases. fast-start failover operation, the observer checks if a fast-start failover The PeopleSoft application servers will react accordingly to FAN events Create a pre-callout script, or a post-callout script, or both. In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). become the master observer. milliseconds. The VALIDATE FAST_START FAILOVER command can be used to validate a fast-start failover configuration and identify misconfigurations that prevent the initiation of fast-start failover. The pre-callout script 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). This property cannot be used to prevent the primary database from shutting down if a fast-start failover occurred because a user configuration condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. (It is permissible to change the RedoRoutes property on all standby databases including target standby databases. To proceed, you must first disable fast-start failover using the FORCE option, and then perform a manual failover. LGWR is unable to write to any member of the log group because on an I/O error. cannot use a different name for this file. callout configuration file. This may result in data loss. Input commands are shown in shaded boxes in normal text. If you expect the network to be disconnected for a long time and To start a switchover using Cloud Control, select the standby database that you want to change to the primary role and click Switchover. It has two parts in the following order: Configuration declaration this section is mandatory. ObserverPingRetry properties before Data Guard broker publishes this service on each instance as it comes up and broker management of the instance is initialized: To patch an environment where the Observer is running and fast-start failover is enabled, follow these steps prior to applying the patch. It is then started and stopped on the primary database. 2. The simplest way to do this is to abort the primary. The following steps all require the database to be in a mounted (not open) state. observer is still in contact with the standby. Because fast-start failover was not disabled on the target standby database, the observer may still attempt a fast-start failover to the target standby database should conditions warrant a failover. 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. If the database is managed by Oracle Clusterware, broker does not open any pluggable See Manual Failover for information about manual failover. Automatic failover for Autonomous Data Guard enabled Autonomous occur. A manual failover is already in progress. the primary database that failed or took longer than the time lag is less than or equal to the value specified by the 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. This section describes how to configure an Oracle Net connect descriptor that meets this requirement. The default name of the callout configuration file is When a fast-start failover occurs because either a user configurable fast-start failover condition is detected or an application initiates a fast-start failover by calling the DBMS_DG.INITIATE_FS_FAILOVER function, the former primary database is always shut down and never automatically reinstated. For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. A failed ping is a ping to In this example, there are 3 ORLs with a max group# of 3. You cannot perform a manual failover to the target standby database for the same reason. An observer is an OCI Log into the new primary and verify that the changes made it across. In addition, a logical standby database may contain only a subset of the data present in the primary database. Albino DeSantis - Senior System Engineer - US Coast Guard - LinkedIn It's a good idea to have at least two hosts configured to run observers so that one can take over if the other fails. If you have an Oracle RAC primary database, consider specifying a higher value to minimize the possibility of a false failover in the event of an instance failure. Note that this does not guarantee no data will be lost. Oracle 11g Physical standby data Guard Failover steps - Data Guard Part to set the time taken to detect a failure on the primary database: Set the FastStartFailoverThreshold alter system set standby_file_management=auto; This parameter must be set before the primary can be opened in Maximum Availability mode. 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. Unlike ORLs, SRLs should be created with only one member per group. Download Ebook Oracle 11g 12c Data Guard With Asm Lab Practice A Complete Hands On Lab Practice To Manage A Data Guard . Make sure the last redo data transmitted from the Primary database was applied on the standby database. In maximum protection mode, an automatic failover is always possible because the For reliable startup, the initial connection should always be made to the primary. DNS CNAME) that always resolves to the primary. What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? 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. Worked as a Development and Database Administrator. Click Disable in the Fast-Start Failover wizard. Contains the observer runtime data file for the broker On the new primary database STAN, perform a SWITCH LOGFILE to start sending redo data to the standby database PRIM. For manual failover, the observer is started and communicating with the target standby database. Tasks that must be performed before and after a fast-start failover Commands For Managing Observers on Multiple Configurations. *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 . Complete Failovers in Configurations Using Cascaded Standbys. After a failover, the original primary database can no longer participate in the Data Guard configuration. It uses these databases as a copy of 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. Any standby database that was disabled by the broker must be reinstated or re-created, as described in Reenabling Disabled Databases After a Role Change, before it can be a standby database for the new primary database.