For Maximum Availability environments, change this to synchronous. All database connections associated with the observer, including the initial connection, must use dedicated server connections. The redo transport mode used to send redo to the target standby database or the database currently in the primary role. Stopping a Specific Observer When There are Multiple Observers. 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. Then, But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). file (fsfo.dat). 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. 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. An immediate failover is the fastest type of failover. Change the failover target to the standby being switched over to, Change the failover target to the desired standby. second. fast-start failover succeeds, if a post-callout script is specified in the fast-start Before stopping an observer, note the following: The observer does not stop immediately when you issue the STOP OBSERVER command. fast-start failover through Cloud Control. The following table summarizes which standby types are supported in which protection modes when fast-start failover is enabled. LGWR is unable to write to any member of the log group because on an I/O error. configuration property. When you start a switchover, the broker verifies that at least one standby database, including the primary database that is about to be transitioned to the standby role, is configured to support the overall protection mode (maximum protection, maximum availability, or maximum performance) after the switchover is completed. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). Disabling Fast-Start Failover Using DGMGRL. Then set the configuration protection mode to maximum availability. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by time specified by maximum configured A manual failover is already in progress. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. 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 configuration contains both physical and logical standby databases, consider choosing a physical standby database (that has the least amount of unapplied redo) to be the target standby database. Keep this trigger as simple and reliable as possible, limiting it to only what is absolutely necessary at the moment of role transition, since any failures at this point may affect availability. There may or may not be data loss depending upon whether your primary and target standby databases were synchronized at the time of the primary database failure. SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. The same thing happens if a shutdown and startup of either database occurs - the service that is started is the one that matches the role of the database being started. callout configuration scripts fsfo_precallout and This action may result in two databases in the configuration simultaneously assuming the primary database role should fast-start failover occur. 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 connect descriptor must contain the SERVICE_NAME parameter in either case. Now that we know switchovers work, it's time to test failovers. A snapshot standby cannot be the target of a switchover or fast-start failover operation. upheld. database. When you configure data guard using OCI console, the default mode is set to maxprotection. If only a file name is Only two databases, the primary and the failover target, can be in the FSFO configuration at any given time. Any broker configuration name that is referred to must exist in the configuration declaration section. You will have to reinstate or re-create (see Reenabling Disabled Databases After a Role Change) the standby databases after failover has completed. The default group is all the configurations defined in the observer configuration file. If the service has been configured to start automatically (-policy AUTOMATIC), then the service will automatically start only after a database role change. Use synonyms for the keyword you typed, for example, try "application" instead of "software.". Data guard Configuration details:- Login in to Standby Server:- Step:1 Check the database role and open_mode Select name,open_mode,database_role from v$database; variable must have read, write, and execute permissions for the directory owner Many customers use Oracle Database deployed on Amazon Elastic Compute Cloud (Amazon EC2) to run their Oracle E-Business Suite applications. 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. If you want to use one Oracle home to start multiple observers, with each observer monitoring a different fast-start failover configuration, use the FILE qualifier to specify a unique observer configuration file location for each configuration to be monitored. Fast-start failover allows the broker to automatically fail over to a previously chosen standby database in the event of loss of the primary database. To install Oracle Data Guard, you need to create two Azure VMs on the same availability set: The primary VM (myVM1) has a running Oracle instance. 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. using the same SYS credentials you used when you connected to the The target standby database is enabled and is in the APPLY-ON state. Your email address will not be published. Credentials Required for Access to Broker Configurations. It will also alert you to databases that have had Flashback Database disabled at some point after FSFO was enabled. The example assumes that the standby uses the same directory structure as the primary. If a non-zero value is specified for the Oracle Database PL/SQL Packages and Types Reference, Stop the observer from any computer system in the broker configuration, as described in, Start the observer on the new computer system, as described in Step 8 of, Enable fast-start failover using the DGMGRL, Shut down the primary database and the target standby database using either DGMGRL, Oracle Database Global Data Services Concepts and Administration Guide, Oracle Real Application Clusters Administration and Deployment Guide, Configure the connect descriptor for connect-time failover. Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. As a result, there is no guarantee that the observer will not perform a fast-start failover to the target standby database if the observer determines that conditions warrant a failover. To enable fast-start failover with DGMGRL, issue the ENABLE FAST_START FAILOVER command while connected to any database in the broker configuration, including on the observer computer. This nomination is noted in the observer log file and in the broker log file (drc*.log). For each broker configuration on which one or more Change Standby to Primary Database. After the database has been re-created, enable broker management of the re-created standby database by using the DGMGRL ENABLE DATABASE command. Once the observer has initiated a fast-start failover, the primary database shuts down automatically. milliseconds and that of ObserverRetryCount is 10. Metadata for the fuzzy snapshot is stored in the flashback log itself. 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. The current primary database must have its LogXptMode property set accordingly and must have standby redo logs configured. In cases where Controlfile is permanently damaged because of a disk failure. An existing connection which is already closed from the database side would throw an error. 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. only. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . See Installing and Starting the Observer. In this case, only observers on ob1-host and If the FastStartFailoverPmyShutdown configuration property is set to TRUE, the primary database will shut down after FastStartFailoverThreshold seconds has elapsed if redo generation has been stalled and the primary database is unable to reestablish connectivity with either the observer or target standby database. For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. In case of worst situation with data guard primary database, or not available for production than we can activated standby database as a primary production database. For example: Using DGMGRL, you can do this by examining the output of the SHOW CONFIGURATION LAG. There is no impact on your current configuration or on applications. SHOW ObserverConfigFile used to check the runtime property ObserverConfigFile. Fast-start failover is enabled, but this standby database is not the target of the fast-start failover. This section will help you get started with creating a wrapper script to automatically start and restart the FSFO observer. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. To configure fast-start failover in observe-only mode: Fast-start failover will not be triggered if the primary or standby database is shut down normally. 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. To verify the readiness of the fast-start failover configuration, issue the DGMGRL SHOW CONFIGURATION VERBOSE command or the SHOW FAST_START FAILOVER command on the primary database. Stores the observer runtime data file and observer configuration file in A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. If this occurs, run 'stop observer' and try again. Use the oraenv script provided by Oracle. fast-start failover when: A network outage isolates the primary database from the observer and the target standby database before conditions exist that warrant a failover. switch does not happen until the next time the primary contacts the target standby, On Linux/Unix, the directory specified by the DG_ADMIN environment You can disable fast-start failover if necessary, by using the FORCE option. Reenabling Disabled Databases After a Role Change describes how to do this. 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). time specified in the WAIT option. In the restore stage, Flashback Database restores the database to a point prior to the standby_became_primary_scn using the before-image blocks in the Flashback Database logs. Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_DG package. environment variable is set and the specified directory has the If both the observer and designated standby database lose connectivity with the primary database for longer than the number of seconds specified by the FastStartFailoverThreshold configuration property, the observer will initiate a fast-start failover to the standby database. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. Starting the Observer as a Background Process Using 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. data (in seconds) specified by the Download Ebook Oracle 11g 12c Data Guard With Asm Lab Practice A Complete Hands On Lab Practice To Manage A Data Guard . The Marketplace image that you use to create the VMs is Oracle:Oracle-Database-Ee:12.1..2:latest. guaranteed to lose no data. command does not have a network connection to the primary database. Displays the current fast-start failover mode. In maximum availability mode, the behavior depends on the value of the The default value is 30 seconds and the lowest possible value is 5 seconds. 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). The observer does not attempt to reinstate the former primary database. 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. Use the SHOW CONFIGURATION BystandersFollowRoleChange command to see the value of this property. Notice that the former primary is now disabled. Now it will return PRIMARY. Disabling fast-start failover with the FORCE option when connected to the target standby database guarantees that fast-start failover will not occur. observer and the others are backup observers. The minimum detection time is 6 seconds, which is the default The existence of a .suc file, 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. REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. If failover is not possible for some reason, then the master observer will continue checking whether the standby database is ready to fail over. Then, on the Fast-Start Failover Configure page, select the standby database that should be the target of a failover. Only the master observer can coordinate fast-start failover with Data Guard broker. To disable fast-start failover, use the Fast-Start Failover wizard in Cloud Control or the DGMGRL DISABLE FAST_START FAILOVER [FORCE] command. The standby VM (myVM2) has the Oracle software installed only. Another consequence of immediate failover is that all other databases in the configuration are disabled and must be reinstated or re-created before they can serve as standby databases for the new primary database. If the failover target database is an Oracle RAC physical or snapshot standby database, the broker directs Oracle Clusterware to restart all instances that may have been shut down prior to the failover. A database in the primary role will not open until it has verified with the observer that it is still the primary. It may be possible to convert the old Primary into a Standby database now instead of having to do a time consuming duplicate again. It doesn't consider how much of that redo has been applied. Oracle Data Guard work on two database roles Primary and Standby. If errors occur during the disable operation, the broker returns an error message and stops the disable operation. 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. In addition, some standby databases may be disabled by the broker during the failover if the broker detects that they have applied redo beyond where the new primary database had applied. It will return PHYSICAL STANDBY, If the DG_ADMIN environment variable is not defined, or the Once the Oracle instance is transitioned into primary database status in either switchover or failover, the life of the database as the standby ends and its service as the primary database . Use Broker's "show configuration" command to determine FSFO status and the "show database
Henry James Zahn,
34 Club Drive In Massapequa,
Miriam Defensor Santiago Speech,
Articles D