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The service can be started on the physical standby only after the redo generated by starting the service has been applied. These requirements are supplemental to those described in the documents previously referenced and in the following client-specific guides: Oracle Data Provider for .NET Developer's Guide for Microsoft Windows. not already enabled, the observer waits until fast-start failover Switchover to a logical standby database is disallowed when the configuration is operating in maximum protection mode. Automatic failover quickly and reliably fails over the standby Autonomous database to the primary database role, without requiring you to perform any manual steps. Dataguard switchover and failover steps in Oracle The name of the callout configuration scripts is specified in Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. In the following example, ObserverReconnect is set to 30 seconds. This list describes conditions in which the broker cannot automatically reinstate the former primary database. 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. By default, the observer uses the same connect identifiers used by Data Guard for redo transfer and information exchange between the primary and standby ( DGConnectIdentifier in Oracle Database 11g, InitialConnectIdentifier in Oracle Database 10g). In addition, the database to be reinstated and the new Observer uses the value of the DGConnectIdentifier property to connect to and monitor the primary and target standby databases. However, there may be situations in which you must disable fast-start failover when The current primary database must have its LogXptMode property set accordingly and must have standby redo logs configured. These tasks assume that you are connected as SYS or SYSDG and that a primary and standby database are already set up in a broker configuration. Flashback Database records the before-image of changed blocks. Use the oraenv script provided by Oracle. Verify the standby database instance is mounted. 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 Broker changes database parameters during startup and role transitions via ALTER SYSTEM commands. For more information, see SET MASTEROBSERVER TO. ASYNC. 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. If it exists, and it contains a pre-callout script location, Step 4: Enable Fast-Start Failover Now we are ready to enable FSFO: DGMGRL> enable fast_start failover; Enabled in Zero Data Loss Mode. This file Reinstatement will have to be accomplished by other means (manual or scripted Broker commands). DG_BROKER_START is set to TRUE and DG_BROKER_CONFIG_FILEn are set correctly SQL> sho parameter broker You must also start and stop the SALESRO service on the primary so that it can be started on the standby. An spfile is required to persist these changes. The observer is the key element that separates Data Guard failover from its pre-FSFO role as the plan of last resort to its leading role in a robust high availability solution. The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. the primary database that failed or took longer than the time We will create 4 SRLs starting with group# 11. In fact, failovers are so reliable, fast, and simple that switchovers become the exception rather than the rule. For switchovers, understanding all of the factors can simplify the choice of which standby database to consider as your new primary database. Figure 6-2 shows the observer monitoring a fast-start failover configuration. Reinstating the Former Primary Database in the Broker Configuration for more information about reinstatement. If all the databases do not have the same values, SRVCTL attempts to override the values, which will fail on the physical standby database because it is open read-only. No two observers on the same Data Guard Broker configuration can have the same name. 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. You must ensure that the primary database is shut down prior to performing a manual failover. Set the FastStartFailoverThreshold property to specify the number of seconds you want the observer and target standby database to wait (after detecting the primary database is unavailable) before initiating a failover. If the PreferredObserverHosts property is set for the current The guide makes few assumptions about your existing environment and includes examples for creating a physical standby database and Data Guard Broker configuration. Stores the observer runtime data file and observer configuration file in name of the observer log file is For example: The default value for the FastStartFailoverThreshold property is 30 seconds and the lowest possible value is 6 seconds. Logical standby databases that are disabled during failover can be reinstated. guaranteed to lose no data. If fast-start failover is enabled and the Datafile Write Errors condition is specified, then a fast-start failover is initiated if write errors are encountered in any data files, including temp files, system data files, and undo files. If the failover fails for any reason, it could leave the target standby database inoperable, regardless of whether the target standby database is ready to failover. If the service has been configured to start automatically (-policy AUTOMATIC), then the service will automatically start only after a database role change. If the primary and target standby databases do not have network connectivity or if the database to which you are connected does not have network connectivity with the primary database, consider using DISABLE FAST_START FAILOVER with the FORCE option. 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. After a failover, the original primary database can no longer participate in the Data Guard configuration. If there is another standby database that is available for failover, you can perform a manual failover to that standby database after you first disable fast-start failover using the FORCE option on that standby database. How to Test Data Guard Fast-Start Failover by Shutting Down Primary Theoretically, this method can be used when a data guard failover occurred between the primary and standby database, but not a switchover. (as it might in maximum availability and maximum performance modes). 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. See Prerequisites for more information. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . 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. This is to ensure that the service definition gets propagated to the physical standby database via the redo stream and thus allows for the service to be started on the physical standby database. Notice that the terminal session appears to hang after starting the observer. 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. The other configurations that are not required but they might make your fast-start failover go smoothly. 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. Make sure that xdpyinfo exist under PATH variable. lose no more than the amount of data (in seconds) specified by the In this mode, the FastStartFailoverLagLimit configuration property is set to zero. the SYSDG or SYSDBA privilege. A complete failover also attempts to avoid disabling any standby databases that were not the target of the failover, so that they may continue serving as standby databases to the new primary database. There are two types of failover operations: Graceful or "no-data-loss" failover and Forced or "minimal-data-loss" failover. To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. 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. If failover is not possible for some reason, then the master observer will continue checking whether the standby database is ready to fail over. Choosing the standby database with the smallest transport lag can minimize the amount of data loss and in some cases, incur no data loss at all. A normal shutdown prevents a fast-start failover until the primary database and standby database are connected and communicating again. The observer is perfectly satisfied if all of the redo it needs to meet your durability requirements has been received by the failover target. Installing and starting an observer is an integral part of using fast-start failover and is described in detail in the following sections: Oracle Data Guard Installation explains that you can either install only the Oracle Client Administrator or you can install the complete Oracle Database Enterprise Edition or Personal Edition on the observer system. You can also switch the master observer hosts for a group of configurations to one specific host. Overall Steps:-. prolonged stall, either the observer or target standby database This is because the -role qualifier is taken into account only by Data Guard broker, and at database startup. If a database must be re-created from a copy of the new primary database, it will have the following status: Re-create the standby database from a copy of the primary database and then reenable it, as described in How to Re-create and Reenable a Disabled Database. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. These are the actions the broker performs after you start a complete failover. The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. file (fsfo.dat). When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. Moorestown, New Jersey, United States. A switch-over allows the primary database to switch roles with its standby database. . This section describes how to configure an Oracle Net connect descriptor that meets this requirement. Archiver is unable to archive a redo log because the device is full or unavailable. A broker configuration can belong to multiple groups. You must then re-create it from a copy of the new primary database and reenable it as described in How to Re-create and Reenable a Disabled Database. Create a pre-callout script, or a post-callout script, or both. PRIM>SHUTDOWN IMMEDIATE; 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). FAN events are published using Oracle Notification Services (ONS) for all Oracle integrated database clients in Oracle Database 12c and later. Initiate the failover on the standby database STAN: If it's not, DGB will not allow the failover to continue until the DBA has manually resolved any discrepancies. Indexing is a mechanism by which the underlying data is mapped for faster retrieval. Start the Data Guard listener on both "a" and "b" hosts. 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. The new primary database starts transmitting redo data to the new standby database. When performing a failover in a configuration whose standbys are all of the same type, choose the standby database that has the smallest transport lag. It must appear as the first part of an observer configuration file. 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. Notice that the former primary is now disabled. If a single-instance primary database (either Oracle RAC or non-Oracle RAC), or if all instances of an Oracle RAC primary database fail, the observer attempts a fast-start failover. (See Disabling Fast-Start Failover for important considerations when using the FORCE option.). The service is then configured to be active in the PRIMARY role on the standby database SOUTH, so that it will be active on that database after a role transition. This is typically done for planned maintenance of the primary system. SQL>connect /@STAN as sysdba For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. post-callout script, and pre-callout success file for the broker After step 1 finishes, Switch the original physical standby db STAN to primary role; 1)What are the steps to do Switchover/Failover operation manually in 2-node RAC and 2-node DATAGUARD environment. Log into the new primary and verify that the changes made it across. If there is more than one standby database in the configuration, you must explicitly set the FastStartFailoverTarget property on the primary database to name one or more candidate target standby databases. Therefore, the primary database can continue processing transactions, even if the target standby database fails. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. 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. It will return PHYSICAL STANDBY, Instead, the old primary database must be re-created as a standby from a backup of the new primary using the procedure described in How to Re-create and Reenable a Disabled Database. It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. For this reason, you should first issue this command on the target standby database. The target standby database is enabled and is in the APPLY-ON state. contains important information about the observer. There are prerequisites that must be met before the broker allows you to enable fast-start 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. At a minimum, you must set db_unique_name. You can switch back to the original Primary database later by performing another switch over. value is 10. As a result the observer may still initiate fast-start failover to the target standby database, if conditions warrant a failover. 2. configuration. Oracle 12c-Step by Step Manual Data Guard Switchover, Manual Upgrading Oracle Database From 11.2.0.4 to 12.2.0.1, Automatically Terminated The Blocking Session By Setting MAX_IDLE_BLOCKER_TIME, Apply Patching On Oracle 21c Database Release Update 21.7.0.0.0, Oracle 21c Point In Time Recovery of Pdb Database, Oracle 21c Cloning a PDB Database Using Sqldeveloper Tool. The example uses 10 seconds. Permissions Required by the DG_ADMIN Directory. These commands can be issued from the DGMGRL command line, but it is not necessary to log on prior to using them. This may result in data loss. See Directing a Fast-Start Failover From an Application). See Installing and Starting the Observer. Broker Configuration Has Only One Registered Observer. 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. 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. (Note: 11.1.0.7 adds the StaticConnectIdentifier Broker database property to allow you to specify a different service name.) See Reenabling Disabled Databases After a Role Change. Reenabling Disabled Databases After a Role Change describes how to do this. If any errors occur during either conversion, the broker stops the switchover. Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option. How to Failover to a Standby Database Manually and Rebuild Data Guard How to Implement Fast-Start Failover 11g - Ed Chen Logic Managed recovery process has been stopped between primary and standby database and standby becomes primary database. Note: You can also use TNS aliases defined in the tnsnames.ora file when setting the local_listener parameter. Alternatively, you can query the V$DATABASE view on the target standby database. The master observer cannot connect to the target standby database, What Happens if the Observer Fails? 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. In this mode you will need to consider how much data loss is acceptable in terms of seconds and set the FastStartFailoverLagLimit configuration property accordingly. The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. the primary role, use the PreferredObserverHosts issue commands and interact with the broker configuration. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. See the Cloud Control online help for more information. 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. See Setting the Protection Mode for Your Configuration. The following paragraphs describe the supported availability modes. If the former primary database cannot be reinstated automatically, you can manually reinstate it using either the DGMGRL REINSTATE command or Cloud Control. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. 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. When fast-start failover is disabled, no observer is called the master observer; all observers have the same functionality. 4. Fast Start Failover in Data Guard - ORACLE-HELP ORACLE instance shut down. If a non-zero value is specified for the To protect the files, it's good practice to store them in separate filesystems. OBSERVER command, if this directory does not have the (It is permissible to change the RedoRoutes property on all standby databases including target standby databases. For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. the primary database and the target standby database do not have a network 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. 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. Currently, this state can be detected only when the database is open.