data guard failover steps data guard failover steps

Verify Before Switch-over: It may be possible to convert the old Primary into a Standby database now instead of having to do a time consuming duplicate again. 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. They must be re-created from a copy of the new primary database. Steps for FAILOVER the Dataguard environment operation. In order to maintain separation of Broker and non-Broker activity, a second static service is recommended. You can manually stop a specific observer or all observers. On primary database NORTH, execute the following: On standby database SOUTH, execute the following: Services that are to be active while the database is in the physical standby role must also be created and started on the current primary database regardless of whether the service will be started on that database or not. db_domain . Es gratis registrarse y presentar tus propuestas laborales. observer. When the process is complete, the database will be enabled as a standby database to the new primary database, and Cloud Control displays the Oracle Data Guard Overview page. Now test FSFO failover back to the original primary. FSFO is a feature of Broker which records information about the failover target, how long to wait after a failure before triggering a failover, and other FSFO specific properties. Broker is a Data Guard management utility that maintains state information about a primary and its standby databases. In this case fast-start failover cannot occur because the databases are not ready to failover. Dataguard Switchover Using DGMGRL A switchover is a role reversal between the primary database and one of its standby databases. Note that role changes to logical standby databases always result in physical standby database bystanders being disabled. The following sections describe how to reinstate or reenable a database. This feature enables RMAN to duplicate an existing database over the network without requiring a backup to disk or tape. 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. callout directory. If the switchover occurs to a physical standby database, and the former primary A broker configuration can belong to multiple groups. If necessary, you can shut down the primary or target standby database in a fast-start failover environment. Thus, the validity of the values of these properties is not verified until after the switchover. Any broker configuration name that is referred to must exist in the configuration declaration section. Figure 6-1 Relationship of Primary and Standby Databases and the Observer. If possible, confirm that fast-start failover has not There are many examples, and Ritesh Chhajer offers this example of doing a Data Guard switchover using dgmgrl: 1. The minimum detection time is 6 seconds, which is the default on ob3-host and ob4-host will not If you are performing an immediate failover, then the database role is changed to primary without applying any accumulated redo data. The act of switching roles should be a well-planned activity. 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. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. An application should use caution when calling the DBMS_DG.INITIATE_FS_FAILOVER function because the observer will initiate failover, if at all possible. Worked as a Development and Database Administrator. Immediate Failovers in Configurations Using Cascaded Standbys. 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. 1. After FSFO is enabled, Broker will continue to check that Flashback Database is enabled during health checks. The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. Thus, the command-line prompt on the observer computer does not 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. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . They cannot be reinstated. Disabling fast-start failover with the FORCE option when connected to the target standby database guarantees that fast-start failover will not occur. Note that the new primary database does not need to be restarted. 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. same permissions. LGWR is unable to write to any member of the log group because on an I/O error. Determining a Database's Readiness to Change Roles. 8.2 Private Cloud Appliance and . The default value is 30 seconds and the lowest possible value is 5 seconds. If this occurs, run 'stop observer' and try again. To enable fast-start failover, both the primary and target standby databases must be running and have connectivity, and satisfy all of the prerequisite conditions listed in Prerequisites for Enabling Fast-Start Failover. The values that indicate FSFO is ready for failover are listed below. With increased latency comes decreased throughput; however, in some cases the difference in throughput may be made up by increasing parallelism. 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". You cannot create the standby DB system in a different AD from the primary DB system. maximum availability and maximum performance modes, to avoid a STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. 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. When DGMGRL starts, if the DG_ADMIN If you want the broker to skip this viability check of bystander standby databases during a complete failover, thus decreasing the overall failover time, set the BystandersFollowRoleChange configuration property to NONE. It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). The following conditions apply when multiple observers are registered for one configuration: When fast-start failover is enabled, one of the observers is the master observer. You can enable fast-start failover from any site while connected to any database in the broker configuration. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. The real test of the configuration is a successful role transition in both directions with both switchover and FSFO failover. If these parameters are modified outside of Broker, it raises a warning. An observer process is integrated in the DGMGRL client-side component of the broker and typically runs on a different computer from the primary or standby databases and from the computer where you manage the broker configuration. FastStartFailoverLagLimit configuration property. Monitor the environment to ensure the primary database is available. $DG_ADMIN/config_ConfigurationSimpleName/callout The broker preserves the protection mode that was in effect prior to the failover. It will not be allowed to open in any event if fast-start failover is enabled. See Sources of Diagnostic Information for details about the broker's drc* log files. It uses the connect identifier specified in the observer configuration file to locate the credentials for a broker configuration from the Oracle wallet. Once the primary database regains connectivity with the target standby database, fast-start failover will be disabled for all the databases in the configuration. If both HVR and Data Guard were running without latency or if no changes were made to the source database at the time of the failover, it can be assumed that all databases are synced and the no extra steps are necessary; the steps for Graceful Failover can be followed. Written by authors well-known for their talent with RAC, Pro Oracle Database 11g RAC on Linux . The only exception to this is failovers to snapshot standby databases. Use the Cloud Control Fast-Start Failover wizard or the DGMGRL ENABLE FAST_START FAILOVER command to enable fast-start failover. first recording that a fast-start failover cannot happen. An observer is an OCI Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. Duplicate configuration names in configuration definitions are not allowed. If the DG_ADMIN environment variable is not set, or the However, there may be exceptions to the recommendation to choose a physical standby database as the target standby database. To verify this change, again query the Database_role column of V$DATABASE. if the observer is not running, The master observer and the target standby database are inconsistent with regard to the current state of the broker configuration, If the protection mode is maximum availability or maximum protection and the target standby database was not synchronized with the primary database at the time the primary database failed, If the protection mode is maximum performance and the apply point of the target standby database lags the redo generation point of the primary database by more than the amount specified by the FastStartFailoverLagLimit configuration property at the time the primary database failed. To specify which observer can be a master observer when a database is in configuration scripts and checks for errors or misconfigurations. 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 exercises the configuration, but triggers failover differently than losing contact with the primary. If the former physical standby database was running with real-time query enabled, the new physical standby database will run with real-time query enabled. 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 detects that Flashback Database was disabled, either manually, or automatically because Flashback Database discovered a problem, Broker signals "ORA-16827: Flashback Database is disabled". times that the observer retries a failed ping before it initiates a The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. the current working directory. If there are multiple observers, then only one of them is the master observer. Notice that the former primary is now disabled. To use a far sync instance with fast-start failover, the far sync instance transport mode must be set to either SYNC or FASTSYNC and the target standby database transport mode must be set to ASYNC. 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. A value of TRUE helps to ensure that an isolated primary database cannot satisfy user queries. We'll start with switchovers. Once fast-start failover is enabled, the broker will ensure that fast-start failover configuration property. The failed primary database requires reinstatement as a new standby database to the new primary. Note the primary and target standby must have connectivity for this command to complete successfully. time, if all the sessions that are connected though the active services Complete Failovers in Configurations Using Cascaded Standbys.