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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). A number of prerequisites must be met on the primary in order to use Fast-Start Failover. Credentials Required for Access to Broker Configurations. How to Failover to a Standby Database Manually and Rebuild Data Guard If the currently configured mode is maximum protection, Cloud Control will downgrade the mode to maximum availability. 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. How to Enable Fast-Start Failover in Oracle Data Guard 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). Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. It has two parts in the following order: Configuration declaration this section is mandatory. lower detection times for primary database failures, you must 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). required permissions, DGMGRL reports an error. Remote login is required, along with a password file, to allow the databases in a Data Guard configuration to connect to each other. Whether or not you need the FORCE option depends mostly on if the primary and target standby database have network connectivity: If the primary and target standby database have network connectivity, and the database to which you are connected has network connectivity with the primary database, the FORCE option has no effect. Oracle Data Guard configuration with DGMGRL. Starting with Oracle Database Release 21c, use the DG_ADMIN In short, the failover is the deformation of the production (primary) database and activating standby database as the primary. callout directory. Oracle 12c-Step by Step Manual Data Guard Failover 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. A manual failover is already in progress. If the new primary database was a primary database in the past, and had block After Oracle Real Application Clusters Administration and Deployment Guide for information about Application Continuity, The broker simplifies switchovers and failovers by allowing you to invoke them using a single key click in Oracle Enterprise Manager Cloud Control (Cloud Control) or a single command in the DGMGRL command-line interface (referred to in this documentation as, Ensure that the standby database you choose to be the target of fast-start failover has its, Oracle Data Guard Concepts and Administration. This exercises the configuration, but triggers failover differently than losing contact with the primary. If the agent is not The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database. In this case, the observer cannot perform a fast-start failover even if conditions warrant a failover. 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. connectivity with target standby. It will return PRIMARY, disable fast-start failover with the FORCE option on the LGWR is unable to write to any member of the log group because on an I/O error. maximum availability and maximum performance modes, to avoid a Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option. ObserverPingRetry properties before This list describes how the overall Oracle Data Guard protection mode is handled after a manual failover (complete or immediate). Its primary job is to perform a failover when conditions permit it to do so without violating the data durability constraints set by the DBA. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. You can also reinstate bystander standby databases that were disabled during a failover operation. FSFO can also be used with logical standbys and an FSFO-enabled configuration may have multiple standbys with a mix of physical and logical, but only one standby can be the failover target at any given time. Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. SWITCHOVER command, and the databases are managed by Oracle isolated. 11.2 rac servicefailover - Albino DeSantis - Senior System Engineer - US Coast Guard - LinkedIn This section lists the steps the master observer takes to determine if a fast-start failover is needed and then to perform one, if necessary. Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. To see if your primary has already met a prerequisite, follow the instructions in the Verify section. Post failover, there are two methods of rebuilding your failed primary Method 1: Rebuild from scratch -> RMAN duplicate Method 2: Flashback database -> only if Flashback was enabled Reinstate failed primary: When you use data guard broker, with just one command, the primary can be rebuilt. This prevents a "split brain" condition if a failover occurs since none of the changes made to the isolated primary can be made permanent. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. If the client uses remote ONS subscription, the client must specify the hostname and port of the ONS daemon(s) of the primary database and each standby database. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. 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. The service can be started on the physical standby only after the redo generated by starting the service has been applied. If the database is not enabled, you will not be able to perform a failover to this database. the observer configuration file is observer.ora. cannot use a different name for this file. To run an observer as a background process, use the DGMGRL command START OBSERVER IN BACKGROUND. Default value is 10 miliseconds. observer, whether it is currently connected to the primary and target standby databases, You can manually stop a specific observer or all observers. operation can be automated using callout scripts. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. ensure that it has the required permissions. Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. This nomination is noted in the observer log file and in the broker log file (drc*.log). Now it will return PRIMARY. In this case fast-start failover cannot occur because the databases are not ready to failover. 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). 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 Use the Cloud Control Fast-Start Failover wizard or the DGMGRL ENABLE FAST_START FAILOVER command to enable fast-start failover. Use the SHOW CONFIGURATION BystandersFollowRoleChange command to see the value of this property. The original primary database can now be configured as a standby. This walkthrough assumes that all ORLs and SRLs on the primary and standby databases are the same size. However, if the standby has had contact from the primary within the period of time specified by the FastStartFailoverThreshold property, the standby prevents the failover attempt. fast-start failover, you can issue the DGMGRL SHOW FAST_START FAILOVER, It is instructive to watch the alert logs on both databases as well as the observer log after aborting the primary to gain insight into what happens during FSFO failover. To see the specific parameter, use the "show database StatusReport" command. One is the master There can be up to four Select name,open_mode,database_role from v$database; Step:2 Cancel the MRP process The following sections describe these topics: Prerequisites for Enabling Fast-Start Failover, Viewing Fast-Start Failover Configuration Statistics and Status, Performance Considerations for Fast-Start Failover, Reinstating the Former Primary Database in the Broker Configuration, Shutting Down Databases In a Fast-Start Failover Environment. the observer on ob2-host to become the master You need to consider all of the options at the time you are building your Oracle Data Guard configuration, including factors such as the characteristics of physical standbys versus logical standbys versus snapshot standbys, the network latency to your standby database sites, the computing capabilities at a future primary database site, and so on. Once an observer is started, no further user interaction is required. enabling fast-start failover. While this eliminates the processing overhead associated with periodically establishing a new observer connection to the primary database, it also prevents the observer from detecting that it is not possible to create new connections to the primary database. What is true about Data Guard setup with fast-start failover? Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs 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. the primary role, use the PreferredObserverHosts For example, perform full level 0 backups weekly and incremental level 1 backups daily. It shuts down or stalls because it is likely a failover has occurred. They must be re-created from a copy of the new primary database. 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. In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). You can switch over or manual failover to a bystander database. /home1/dataguard/config_NorthSales/callout/fsfocallout.ora. This All standbys other than the failover target are considered bystanders (v$database.fs_failover_status = 'BYSTANDER'). Simply use DISABLE FAST_START FAILOVER. Use the oraenv script provided by Oracle. STANDBY>ALTER DATABASE OPEN; MASTEROBSERVERHOSTS, DGMGRL reports an error if the There are prerequisites that must be met before the broker allows you to enable fast-start failover. The log file name is specified with the LOGFILE IS option of the START OBSERVER command. Read-Only Standby and Active Data Guard Physical Standby Database SWITCHOVER & FAILOVER Operations If you don't already have a Flash Recovery Area (FRA), you will need to create one for Flashback Database. present, you must start the observer manually using the following 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). North_Sales is in the primary role. The default group is all the configurations defined in the observer configuration file. Thus, the validity of the values of these properties is not verified until after the switchover. The minimum allowable limit is 10 seconds. It doesn't consider how much of that redo has been applied. If errors occur during the disable operation, the broker returns an error message and stops the disable operation. Broker will validate the configuration, set parameters on both databases, and start managed recovery. The failed primary database requires reinstatement as a new standby database to the new primary. Example 6-2 Sample Observer Configuration File. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. 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). Maximum availability SYNC or FASTSYNC or ASYNC, Maximum performance SYNC or FASTSYNC or 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. There are configuration requirements that must be met in order to publish and properly handle FAN events generated as the result of a broker-managed failover. Whereas a switchover to a logical standby database will invalidate and disable all of the physical and snapshot standby databases in the configuration. If this Initiate the failover on the standby database STAN: Flashback Database stores its logs in the Flash Recovery Area (FRA), so the FRA must be large enough to store at least 60 minutes of Flashback Database history. 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. instructions for the DGMGRL command-line interface. Except for testing purposes, it is not recommended that you start more than one observer on the same host for a Data Guard broker configuration. The configuration and database status report the same error messages as are returned when there is only one registered observer. Ensure SPFILE is used SQL> sho parameter spfile 2. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . 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. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). failure on the primary database. FAN events are always published through ONS. FSFO enabled configurations having multiple standbys cannot switchover to a standby that is not the failover target. The example uses 10 seconds. The broker first converts the original primary database to run in the standby role. This may result in two databases in the configuration simultaneously assuming the primary database role. Upon detecting the break in communication, the observer attempts to reestablish a connection with the primary database for the amount of time defined by the FastStartFailoverThreshold property before initiating a fast-start failover. Connect-Time Failover to Standby Database - Ed Chen Logic 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. 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. ORACLE-BASE - Data Guard Is possible if the target standby database displays SYNCHRONIZED and the FS_FAILOVER_OBSERVER_PRESENT column displays YES. DGMGRL. You must use the Oracle wallet to store the credentials for all broker configurations to be managed. Most of the network services used in a FSFO environment may use dynamic registration, but to enable Broker to restart instances during role transitions or during reinstatement after a failover, you must define a static service named db_unique_name_dgmgrl. Issue the following commands on Primary database and Standby database to find out: If these parameters are modified outside of Broker, it raises a warning. distance. These Stopping the observer does not disable fast-start failover. This is The Data Guard broker and the secondary database both run the observer and observe the primary database for downtime. The word ALL cannot be used as a group name because it is a reserved keyword. See Manual Failover for information about manual failover. The VALIDATE FAST_START FAILOVER command parses the callout Additionally, the new master observer is identified in the output shown for the SHOW FAST_START FAILOVER and SHOW OBSERVER commands. If the observer finds that the database is no longer the primary, it will attempt to reinstate it as the failover target standby. 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. See Installing and Starting the Observer. The required attributes vary depending on your configuration (including whether your environment is Oracle RAC-based or single-instance). You can start, stop, and show observers for a group of configurations. The first step in reinstatement is to flash the database back to the SCN where the standby became the primary (v$database.standby_became_primary_scn on the new primary). If the target standby database is ready for failover, then the master observer immediately directs the target standby database to fail over to the primary database role. How to switch roles in Oracle Data Guard - The Geek Diary command is submitted successfully, the command-line prompt on the environment variable is set and the specified directory has the Cancel MRP process. Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. The following is an example of querying the V$FS_FAILOVER_STATS view: Disabling fast-start failover prevents the observer from initiating a failover to the target standby database. (as it might in maximum availability and maximum performance modes). set the ObserverPingInterval and A failover may or may not result in data loss depending on the protection mode in effect at the time of the failover. We suggest you try the following to help find what youre looking for: This document will guide you through configuringOracle Data GuardFast-Start Failover (FSFO) using a physical standby database. You can switch back to the original Primary database later by performing another switch over. The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. Make sure that your OS environment on the standby is setup. See the START OBSERVER Oracle 19c-Step by Step Manual Data Guard Failover See "Database Service Configuration Requirements" for additional information about how the broker interacts with Oracle Restart. Look for the desired data in the RAM. Alternatively, you can query the V$DATABASE view on the target standby 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. automatic failover feature in configurations set up for zero data loss protection at any Contains the observer runtime data file for the broker WAIT option, broker waits for the amount of configuration property. 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. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . The connect-identifier is a TNS alias defined in tnsnames.ora through which all instances of all databases in this Data Guard broker configuration can be reached. The group of broker configurations to be managed is declared in the observer configuration file. callout configuration scripts fsfo_precallout and After you click the Reinstate button, Cloud Control begins reinstating the database. Issue the following command while connected to any database in the broker configuration, except the database that is to be reinstated: The newly reinstated standby database will begin serving as a standby database to the new primary database. If possible, confirm that fast-start failover has not . DG BrokerDG BrokerData Guard BrokerOracleDGRMAN Duplicate . 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. Moorestown, New Jersey, United States. The broker automatically reenables the database as part of reinstating it.