The following paragraphs describe the supported availability modes. The simplest way to do this is to abort the primary. expires. session. The NetTimeout property specifies the number of seconds LGWR will block waiting for acknowledgment from the standby in synchronous mode before considering the connection lost (corresponds to the NET_TIMEOUT option of log_archive_dest_n). If the Broker configuration is changed to make a bystander the new failover target (probably a good idea if the failed database will be down for a while), the observer will not automatically reinstate the former primary because it is no longer part of the FSFO configuration. It will return PHYSICAL STANDBY, This not only saves time and minimizes problems by automating an otherwise manual process, it exercises your failover and DR procedures with every flip so that you know the FSFO configuration is sound and, in a real emergency, everyone knows what to do. 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. Execute the following on primary database NORTH: Execute the following on the physical standby database SOUTH: If the broker now performs a switchover or failover, it automatically starts the SALES service on the correct database, based on the database's role. the location of the observer log file, and the location of the observer runtime data under the $DG_ADMIN directory. The Oracle Database 10g FSFO observer is limited to using the default username and password defined in the wallet. The values that indicate FSFO is ready for failover are listed below. database. Manual failover gives you control over exactly when a failover occurs and to which target standby database. Stop the observer using the DGMGRL STOP OBSERVER command. The minimum detection time is 6 seconds, which is the default The RedoRoutes property on the primary if the new value would result in the primary not being able to ship redo to the current fast-start failover target standby. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. This support note is available at http://support.oracle.com. All Data Guard environments should enable force logging at the database level in order to guard against nologging tablespaces from being added. To start a switchover using Cloud Control, select the standby database that you want to change to the primary role and click Switchover. Steps for FAILOVER the Dataguard environment 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). 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. 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). More specifically, we can have an asynchronous second read-only Managed instance in the same or in a different region. For this build, we will use a single physical standby database. SQL>SHUTDOWN IMMEDIATE; The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. Monitor the environment to ensure the primary database is available. become the master observer. Broker will verify that the configuration meets all prerequisites before enabling FSFO and will report any problems it finds. 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. OBSERVER command, if this directory does not have the Enabling Fast-Start Failover Task 1: Determine Which of the Available Standby Databases is the Best Target for the Failover, Enabling Fast-Start Failover Task 2: Specify Target Standbys with the FastStartFailoverTarget Configuration Property, Enabling Fast-Start Failover Task 3: Determine the Protection Mode You Want, Enabling Fast-Start Failover Task 4: Set the FastStartFailoverThreshold Configuration Property, Enabling Fast-Start Failover Task 5: Set Other Properties Related to Fast-Start Failover (Optional), Enabling Fast-Start Failover Task 6: Enable Additional Fast-Start Failover Conditions (Optional), Enabling Fast-Start Failover Task 7: Using DGMGRL or Cloud Control, Enabling Fast-Start Failover Task 8: Start the Observer, Enabling Fast-Start Failover Task 9: Verify the Fast-Start Failover Environment. $DG_ADMIN/config_ConfigurationSimpleName/callout For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. However, there may be exceptions to the recommendation to choose a physical standby database as the target standby database. Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. Steps that require the primary to be in a mounted (not open) state are grouped together in the section below entitled Steps Requiring a Bounce of the Primary. In cases where about starting the observer as a background A fast-start failover occurred because a user-configurable condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. What is true about Data Guard setup with fast-start failover? Remember to check Flashback Database history before aborting the primary. Using Cloud Control, you can view the value of the ApplyLag column for each standby database in the Standby Databases section of the Oracle Data Guard Overview page. The services include switchover, switchback and failover. This property specifies the amount of data, in seconds, that the target standby database can lag behind the primary database in terms of redo applied. For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. During the failover to the physical standby database, the Oracle 11g DGB performs the following steps: First, it validates that the target standby database is ready to accept the primary role. 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). This method will disable fast-start failover on all databases in the broker configuration. Setting it to 'FALSE' leaves the database open and stalled until it is terminated or signaled to proceed in the event a failover did not take place (e.g. When this command is issued, the actual Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_DG package. 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. (Oracle Call Interface) client that connects to the primary and target standby databases See Enabling Fast-Start Failover for more information. The terminal session will appear to hang at this point. on ob3-host and ob4-host will not See the Cloud Control online help for more information. MASTEROBSERHOST TO command. In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). db_domain . SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; The default name of the callout configuration file is value of the FastStartFailoverThreshold property. To allow the master observer to automatically reinstate the former primary database, the database must be started and mounted. Open another prompt and connect to SQLPLUS: When you configure data guard using OCI console, the default mode is set to maxprotection. This is the recommended method for disabling fast-start failover. automatic failover feature in configurations set up for zero data loss protection at any 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. PDBs. You can query the V$FS_FAILOVER_STATS view on the primary database to display statistics about fast-start failovers that have occurred on the system. If you are more concerned about the performance of the primary database than a minimal loss of data, consider enabling fast-start failover when the configuration protection mode is set to maximum performance. The failed primary database requires reinstatement as a new standby database to the new primary. Table 6-3 FS_FAILOVER_OBSERVER_PRESENT Column of the V$DATABASE View, The master observer is currently connected to the local database, The master observer is not connected to the local database. (Note that the target standby cannot be a far-sync instance. The standby database must be re-created or reinstated before it can serve as a standby for the new 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. You can upgrade the protection mode later, if necessary, as described in Setting the Protection Mode for Your Configuration. Other logical standby bystander databases in the broker configuration will remain viable after the switchover. This section describes how to configure and verify each prerequisite. But it will also continue trying to reconnect to the primary database indefinitely. If the DG_ADMIN environment variable is not set, or the This This lets you take advantage of the broker's configuration named ConfigurationSimpleName. 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. Use the EMCLI verb dg_configure_observers. It also requires Flashback Database to be enabled on both the primary and target standby databases. The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. This list contains some recommendations to obtain better performance when using fast-start failover. Duplicate configuration names in configuration definitions are not allowed. instructions for the DGMGRL command-line interface. database is managed by Oracle Clusterware, broker directs Oracle Clusterware to 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. This walkthrough assumes that all ORLs and SRLs on the primary and standby databases are the same size. Now it will return PRIMARY. Observer sites monitor the fast-start failover environment. If this After fast-start failover is enabled and up to four observers are started, one observer is nominated as the master observer that continuously monitors the environment to ensure the primary database is available. This list describes conditions in which the broker cannot automatically reinstate the former primary database. failover to the target standby database. Data Guard Configuration Details:-. 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. Suppose you have a primary database, BOSTON, and a standby database, CHICAGO. Disabling fast-start failover does not stop the observer. 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. ASYNC. A failover is a role transition in which one of the standby databases is transitioned to the primary role after the primary database (all instances in the case of an Oracle RAC database) fails or has become unreachable. 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. However, if you want the observer to reconnect to the primary database periodically as a means of testing the health of the network connection to the primary, then use the ObserverReconnect configuration property. If the target is a snapshot standby database, the broker first converts the database back to a physical standby and then starts Redo Apply to apply all the accumulated redo before completing the failover and opening the database as a primary 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. For each temporary table, verifying that temporary files associated with that table on the primary database also exist on the standby database. Opens the new primary database in read/write mode. LGWR is unable to write to any member of the log group because on an I/O error. 11.2 rac servicefailover 2020-01-28 ORACLE ORACLE RAC/ASM RAC112. Worked as a Development and Database Administrator. When a serious condition uniquely known to an application is detected, the application can call the DBMS_DG.INITIATE_FS_FAILOVER function to initiate an immediate fast-start failover. After step 3 completes, you can open the new Primary database STAN: 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. 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. This configuration property establishes an acceptable limit, in seconds, that the standby is allowed to fall behind the primary in terms of redo applied, beyond which a fast-start failover will not be allowed. prolonged stall, either the observer or target standby database Use the wrapper script to start the observer process when the observer host boots or to restart it if it dies. 1. 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. alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. When you run commands that need access to the observer 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. Add an entry to the oratab file for the standby, db1:/u01/app/oracle/product/11.1.0/db_1:Y. Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. Fast-start failover is enabled, but this standby database is not the target of the fast-start failover. 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". occurred to the target standby database prior to disabling fast-start SQL> Select Database_role from v$Database; You can issue a Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database. A failover may or may not result in data loss depending on the protection mode in effect at the time of the failover. Some properties have changed between those releases. However, re-enabling Flashback Database will require a bounce since the database must be mounted and not open. The following assumes that the standby host has been setup according to Oracle's recommendations and that the operating system, accounts, security, resource limits, directory structure, etc. Oracle also provides Fast Application Notification (FAN) for OCI clients and Fast Connect Failover for JDBC clients. Use Cloud Control or DGMGRL to perform either a complete (recommended) or an immediate failover. However, the event notifying a failover is only published for database services that have been configured to be active while the database is in the primary role on the new primary database. FastStartFailoverLagLimit To perform specified actions before or after a fast-start failover 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. After the database has been re-created, enable broker management of the re-created standby database by using the DGMGRL ENABLE DATABASE command. After step 1 finishes, Switch the original physical standby db STAN to primary role; To see Manual Switch Over Manual SwitchOver in Oracle To see Manual Fail Over Manual Failover in Data Guard With Oracle Data Guard [] Any broker configuration name that is referred to must exist in the configuration declaration section. Before beginning a failover, first determine that there is no possibility of recovering the primary database in a timely manner, and ensure that the primary database is shut down. Broker is a Data Guard management utility that maintains state information about a primary and its standby databases.