FSFO builds upon a number of other Oracle technologies and features such as Data Guard, Flashback Database, and Data Guard Broker. ZERO DATA LOSS: Fast-start failover is enabled with zero data loss. See Performing Manual Role Changes When Fast-Start Failover Is Enabled for more information. 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. After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. To issue commands and interact with the Therefore, the detection time can be reduced to nearly Metadata for the fuzzy snapshot is stored in the flashback log itself. 3. There can be up to four observers for a single Data Guard configuration. If the DG_ADMIN environment variable is not set, or the ConfigurationSimpleName is created. usually within three seconds if fast-start failover is enabled. FSFO configurations in Maximum Performance mode may limit potential data loss by specifying the maximum allowable age of transactions that are lost during a failover. After an immediate failover completes, all the standby databases in the configuration, regardless of their type, are disabled. 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. Controlfile is permanently damaged because of a disk failure. Restart the database to the mounted state, Use Cloud Control or DGMGRL to reinstate the database. If the primary database has multiple standby databases, then you can specify multiple fast-start failover targets, using the FastStartFailoverTarget property. 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. After setting local_listener, register the database with the listener and verify the services have been registered. If the new primary database was a primary database in the past, and had block The price for this guarantee is increased commit latency ( log file sync waits). The configuration and database status report that the observer is not running and return one of the following status messages: While the configuration is in the unobserved state, fast-start failover cannot happen. If only a path is specified, the files are This document only talks about switchover involving physical standby database. Step 4: Enable Fast-Start Failover Now we are ready to enable FSFO: DGMGRL> enable fast_start failover; Enabled in Zero Data Loss Mode. For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. value of the FastStartFailoverThreshold property. This example shows the verbose mode of the 'show configuration' command that provides FSFO-specific information. Specifying Preferred Observers Based on Current Primary. (Yes, bystanders need Flashback Database too). 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. See Prerequisites for more information. Sign in to Azure an alias of the broker configuration name. The Appendix provides information oncreating a simple wrapper script to start the observer as a background process. If you have an Oracle RAC primary database, consider specifying a higher value to minimize the possibility of a false failover in the event of an instance failure. If both of those observers are unavailable, the observers 1)What are the steps to do Switchover/Failover operation manually in 2-node RAC and 2-node DATAGUARD environment. 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. Please contact us at [email protected]. Set the ObserverPingInterval and Add the SRLs. Busca trabajos relacionados con New sql server failover cluster installation greyed out o contrata en el mercado de freelancing ms grande del mundo con ms de 22m de trabajos. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. Fast-start failover enables the Data Guard broker to rapidly and automatically failover to a previously chosen standby database without requiring manual intervention. An observer is a separate OCI client-side component that run on a different computer from the primary and standby databases and monitors the availability of the primary database. During a complete failover, the broker performs the failover steps described in How the Broker Performs a Complete Failover Operation. 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. When the primary database and the target standby database regain network connectivity, the broker will disable fast-start failover for the entire broker configuration. . Data Guard Configuration Details:-. See Manual Failover for complete information about manual failovers. Stopping the observer does not disable fast-start failover. In 10g, a single wallet can be used for multiple observers, but they must all use the same SYS password. Data Guard. The example below takes advantage of the 11g RMAN Active Database Duplication feature. Check the Undo tablespace Usage in Oracle, Exclude/Include option in EXPDP and IMPDP Datapump, Missing Dependencies Python Core / win32api, Stop the EXPDP/IMPDP Datapump Job in Oracle, Find the temp usage by sessions in Oracle, Create & grant permission to directory in Oracle, Check the Patch Applied to the Oracle Database. Note that this does not guarantee no data will be lost. The observer configuration file is a text file and the syntax to define observers and groups is similar to that used in the listener.ora or tnsnames.ora files. 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. 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. Presetting database properties related to redo transport services, such as LogXptMode, NetTimeout, StandbyArchiveLocation, StandbyAlternateLocation, and RedoRoutes. 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. The failed primary database requires reinstatement as a new standby database to the new primary. See the Oracle Reference and Data Guard Administrator guides for your release for details. Check the database role,open_mode in standby server. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). File. See theFlashback Database section above for information on storage requirements. The connect descriptor can be configured in one of two ways: Oracle Database PL/SQL Language Reference for more information about the DB_ROLE_CHANGE system event. If there is more than one registered observer, then this command returns an error; a name is required if there is more than one observer. this directory are used to store the files related to the See Oracle Enterprise Manager Command Line Interface. If the observer is unable to regain a connection to the primary database within the specified time, and the target standby database is ready for fast-start failover, then fast-start failover ensues. 3. All Data Guard environments should enable force logging at the database level in order to guard against nologging tablespaces from being added. In the following example, ObserverReconnect is set to 30 seconds. You can also query the V$FS_FAILOVER_STATS view to display statistics about fast-start failover occurring on the system. Performing a Manual Failover Task 1: Determine Which of the Available Standby Databases is the Best Target for the Failover, Performing a Manual Failover Task 2: Start the Failover, Performing a Manual Failover Task 3: Reset the Protection Mode, Performing a Manual Failover Task 4: Re-establish a Disaster-Recovery Configuration. Archiver is unable to archive a redo log because the device is full or unavailable. If you initiated a complete failover and it fails, you might need to use immediate failover. Expected output is shown in blue text. The behavior of the broker if the master observer fails depends on whether the broker configuration has one observer or multiple observers. Now it will return PRIMARY. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: The application needs to catch this error and respond accordingly. 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. If that metadata is pushed out, Oracle can no longer find a fuzzy snapshot so it will not be able to flash back. The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. We'll start it interactively for now to verify that everything's working. Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. When the conditions for fast-start failover are met, the Broker adds messages to the observer log and broker log indicating that fast-start failover would have been initiated. Oracle Data Guard Concepts and Administration provides information about setting up the databases in preparation of a switchover. 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. SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. configuration named ConfigurationSimpleName. observer as a foreground process. The time interval specified by the FastStartFailoverThreshold property is ignored if the master observer detects that a user-configurable condition has occurred or if a fast-start failover has been requested by the DBMS_DG.INITIATE_FS_FAILOVER function. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . An spfile is required to persist these changes. command on the observer computer: The observer is a continuously executing process that is FAN events are always published through ONS. about starting the observer as a background Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. You cannot perform a manual failover to the target standby database for the same reason. Enabling fast-start failover in a configuration operating in maximum performance mode provides better overall performance on the primary database because redo data is sent asynchronously to the target standby database. fast-start failover to the target standby database if conditions warrant a failover. The My Oracle Support note 1625597.1 at http://support.oracle.com for information about compatibility requirements between the observer and DGMGRL, Starting Multiple Observers on a Data Guard Broker Configuration. See FastStartFailoverTarget for more information about this property. 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. 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 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. In this case fast-start failover cannot occur because the databases are not ready to failover. For more information, see SET MASTEROBSERVER TO. The contains important information about the observer. Automatic failover quickly and reliably fails over the standby Autonomous database to the primary database role, without requiring you to perform any manual steps. After the failover completes, the former primary database is automatically reinstated as a standby database when a connection to it is reestablished, if the FastStartFailoverAutoReinstate configuration property is set to TRUE. The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. ASYNC. STOP OBSERVING, and SET Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. fast-start failover operation, the observer checks if a fast-start failover The following steps all require the database to be in a mounted (not open) state. When the standby becomes available again, the primary and standby re-synchronize and resume synchronous redo transfer. Fast-start failover can be used only in a broker configuration and can be configured only through DGMGRL or Cloud Control. Starting with Oracle Database Release 21c, use the DG_ADMIN specified, the file is stored in an appropriate directory under the broker's observer is still in contact with the standby. The original primary database can now be configured as a standby. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . SQL>ALTER SYSTEM SWITCH LOGFILE; The master observer waits the number of seconds specified by the FastStartFailoverThreshold configuration property before attempting a fast-start failover when the primary database has crashed or has lost connectivity with the observer, as in the following situations: The primary database loses its connections with both the observer and target standby database. The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. By default, the broker always determines whether bystander standby databases will be viable standby databases for the new primary when performing a complete failover. If the value is non-zero, failover is possible any time the standby database's apply These are some points to consider before you begin a switchover. The observer does not need to coordinate fast-start failover when fast-start failover is disabled, so the primary and target standby do not nominate a master observer until fast-start failover is enabled. If the DG_ADMIN environment variable is not defined, or the The service can be started on the physical standby only after the redo generated by starting the service has been applied. switch does not happen until the next time the primary contacts the target standby, For example: Using DGMGRL, you can do this by examining the output of the SHOW CONFIGURATION LAG. For this build, we will use a single physical standby database. 4. The primary database can be reinstated if it had flashback database enabled. Note that if the V$DATABASE.FS_FAILOVER_STATUS column has a value of DISABLED, then any values returned for the remaining columns related to fast-start failover (V$DATABASE.FS_FAILOVER_*) become irrelevant. As mentioned above, Maximum Availability mode is mandatory for Oracle Database 10g and optional for Oracle Database 11g. When querying the V$DATABASE view, pay special attention to the following: The FS_FAILOVER_STATUS column, which can contain the values described in Table 6-2. observer and the others are backup observers. If Flashback Database fails, automatic reinstatement stops and you will have to perform a manual SCN-based recovery to the standby_became_primary_scn and complete the reinstatement. Permissions Required by the DG_ADMIN Directory. isolated. The simplest way to do this is to abort the primary. 5. Some of the statistics that can be monitored are as follows: LAST_FAILOVER_TIME that shows the timestamp of last fast-start failover, LAST_FAILOVER_REASON that shows the reason for the last fast-start failover. After step 1 finishes, Switch the original physical standby db STAN to primary role; Fast-Start Failover allows Data Guard to automatically failover to a previously chosen standby database without requiring manual intervention to invoke the failover. If you like a connect-time failover to survive across a data guard switchover, you need another way to do it. A failover to a physical standby database is preferable because it is likely that all standby databases in the configuration will still be available as standby databases to the new primary database after the failover operation completes. Note that the database will not open at this point. Now test FSFO failover back to the original primary. directory does not have the required permissions, broker does the following: When you run DGMGRL commands, if a path and file name are explicitly specified for required permissions, fast-start failover callouts will fail. Verify the target standby database is ready for failover. You can find detailed information about all observers, including master observers and backup observers, in the V$FS_FAILOVER_OBSERVERS view. Stores the observer runtime data file and observer configuration file in The ObserverReconnect configuration property specifies how often the observer establishes a new connection to the primary database. The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. Note the use of "/@" to login using the wallet. FastStartFailoverLagLimit property. An observer can be moved from one computer to another through a process of stopping it on one system and and re-starting it on another. The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. 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). US Coast Guard Auxiliary. In Oracle RAC configurations, the Inaccessible Logfile and Stuck Archiver health conditions may only be applicable to a single instance. time specified in the WAIT option. All other registered observers are considered to be backup observers. the current working directory. In an environment where there are multiple observers configured, stopping the master observer is not allowed unless it is the last running observer. For each broker configuration on which one or more See Sources of Diagnostic Information for details about the broker's drc* log files. 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. As shown in the table, fast-start failover can be enabled in maximum availability Switches roles between the primary and standby databases. 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. This support note is available at http://support.oracle.com. STANDBY>connect /@STAN as sysdba The failover was to a logical standby database. To see the specific parameter, use the "show database StatusReport" command. This is typically done for planned maintenance of the primary system. Do not attempt to reinstate the old primary database if an ORA-752 or ORA-600 [3020] error has occurred at the failover target. Use the EMCLI verb dg_configure_observers. If the primary is unable to contact the standby after a user specified period of time (NET_TIMEOUT option of log_archive_dest_ n), it drops out of synchronous transfer mode and begins operating as though it were in Maximum Performance mode. RAM). In short, the failover is the deformation of the production (primary) database and activating standby database as the primary. For instance, you could log into the system running observer1 to stop observer2. occurred to the target standby database prior to disabling fast-start 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. 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. 12c upgrade, The below commands will help to bring up standby as primary, https://www.linkedin.com/in/hari-prasath-aa65bb19/, https://www.facebook.com/groups/894402327369506/. Database hosts are referred to as "a" and "b" hosts and the databases themselves are referred to as the "a" and "b" databases. failover to the target standby database. It will also alert you to databases that have had Flashback Database disabled at some point after FSFO was enabled. SQL> Select Database_role from v$Database; In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). Each observer is identified by a name that you supply when you issue the START OBSERVER command. This prevents a "split brain" condition if a failover occurs since none of the changes made to the isolated primary can be made permanent. The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. Click Disable in the Fast-Start Failover wizard. Failover automation ensures a seamless transition from the primary database to a synchronized standby database in cases of failure, while ensuring database availability by replaying uncommitted in-flight transactions. In a separate terminal session, verify the configuration. irrespective of its content, indicates that the script executed successfully. Note that a switchover operation may be started before the specified wait times that the observer retries a failed ping before it initiates a operation: Example 6-1 Fast-start Failover Configuration Disabling Fast-Start Failover Using DGMGRL. In disaster situations where a failover is necessary, you may be more limited as to which standby database is the best one to pick up the failed primary database's activities. 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. Valid values are >= 10. Have a means of notifying someone if standby apply falls too far behind. Create or update the fast-start failover callout configuration file and include The environment is a single instance database without any grid Infrastructure components. There are two types of failover operations: Graceful or "no-data-loss" failover and Forced or "minimal-data-loss" failover. During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. To enable fast-start failover in Cloud Control, use the Fast-Start Failover wizard. Figure 6-1 shows the relationships between the primary database, target standby database, and observer during fast-start failover: Before Fast-Start Failover: Oracle Data Guard is operating in a steady state, with the primary database transmitting redo data to the target standby database and the observer monitoring the state of the entire configuration. 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. guaranteed to lose no data. See the "DISABLE FAST_START FAILOVER" command in Oracle Data Guard Command-Line Interface Reference for more information. The group of broker configurations to be managed is declared in the observer configuration file. alter database recover managed standby database finish; alter database activate standby database; Managed recovery process has been stopped between primary and standby database and standby becomes primary database. For example: You can find information about the master observer by querying the V$DATABASE view. For each observer, the V$FS_FAILOVER_OBSERVERS view provides the A normal shutdown prevents a fast-start failover until the primary database and standby database are connected and communicating again. The broker disables all of the physical and snapshot standby databases in the configuration. For example, if a physical standby database was in the APPLY-OFF state, it will remain in the APPLY-OFF state. Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. the observer was killed after the stall began, but before the failover timeout had elapsed). configuration property. You can customize fast-start failover setup for a specific application by using the DBMS_DG PL/SQL package. SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; The FORCE option may be the preferred method for disabling This brings up the General Properties page that provides a Reinstate button. In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. 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. For reliable startup, the initial connection should always be made to the primary. RMAN also copies the spfile and password files and you can change the values for individual parameters. To do this, use the SET ObserverConfigFile and SHOW ObserverConfigFile commands. In this mode, no actual changes are made to your Broker configuration. first recording that a fast-start failover cannot happen. 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. Oracle Data Guard Command-Line Interface Reference for more information about these broker commands. This database property is used to specify how the observer should connect to and monitor the primary and standby database. ObserverConnectIdentifier allows you to specify different connect identifiers for the observer to use. 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. See the Cloud Control online help for more information. Broker maintains these parameters by issuing ALTER SYSTEM commands as appropriate during role transitions, database startup/shutdown, and other events. You can disable fast-start failover if necessary, by using the FORCE option. database (if real-time query is enabled). Switch-over steps: Step-A: Shutdown primary database: SQL> shut immediate; Database closed. If the switchover transitions a logical standby database to the primary role, then: The original primary database will be switched to a logical standby role. Twitter:https://twitter.com/hariprasathdba, In broker opens all the PDBs on the new primary database and on the target standby Synopsis. You must set both In case of primary database failure, you will need to perform failover to transition the standby database to the primary role. Do this prior to every failover test. When this property is set to NONE, the broker will disable all bystander standby databases without checking whether they have applied more redo data than the new primary database. SQL>STARTUP; Provides an automatic failover environment that Data Guard broker does not manage or store credentials. In the previous article, we have seen switching the role of Primary and standby database and failover Primary role to Standby database manually. Testing FSFO failover requires simulating loss of the primary. Therefore, the primary database can continue processing transactions, even if the target standby database fails. In Maximum Availability mode, FSFO guarantees that no transaction that has received a commit acknowledgment will be lost during a failover.

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