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. post-callout script, and pre-callout success file for the broker When fast-start failover is enabled, the primary and standby randomly choose one of the registered observers to be the master. Theoretically, this method can be used when a data guard failover occurred between the primary and standby database, but not a switchover. If the database is not enabled, you will not be able to perform a failover to this database. Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. configuration named ConfigurationSimpleName. All standbys other than the failover target are considered bystanders (v$database.fs_failover_status = 'BYSTANDER'). Starting with Oracle Database Release 21c, use the DG_ADMIN That process is shown here. It automatically recovers the maximum amount of redo data for the protection mode the configuration is operating in. If a failure occurs once a reinstatement operation (automatic or manual) is underway, the broker logs the appropriate information in the broker configuration files and broker log files. If you are more concerned about the performance of the primary database than a minimal loss of data, consider enabling fast-start failover when the configuration protection mode is set to maximum performance. It automatically sets Data Guard related database initialization parameters on instance start and role transitions, starts apply services for standbys, and automates many of the administrative tasks associated with maintaining a Data Guard configuration. You can query the V$DATABASE view to verify that the observer is started and the configuration is ready for fast-start failover. Data Guard Switchover/failover to standby The standby database will be activated to serve as the primary database at some point in its life cycle. This is true regardless of the settings for the FastStartFailoverPmyShutdown and FastStartFailoverAutoReinstate configuration properties. Reinstate or re-create standby databases in the configuration that were disabled by the broker. The following table summarizes which standby types are supported in which protection modes when fast-start failover is enabled. But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). See the START OBSERVER Observer sites monitor the fast-start failover environment. Note that the FastStartFailoverThreshold property can be changed even when fast-start failover is enabled. 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. Whether you reinstate or re-create a database depends on whether you performed a switchover or failover, on the type of standby database that was the target of the operation, and on whether or not there are sufficient flashback logs. An immediate failover is the fastest type of failover. If the value is zero, the standby must It wouldn't be much of a test if we didn't verify that our durability constraints were being met, so let's make a change on the primary and see if it survives the failover. These commands can be issued from the DGMGRL command line, but it is not necessary to log on prior to using them. Valid values are >= 100. To move the observer to another computer: There is no need to disable fast-start failover when you move the observer. 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. property. The role change is directed to the same standby database that was specified for the FastStartFailoverTarget database property on the primary database. If the target standby database is a snapshot standby database, all of its instances must be restarted to the mount mode before performing failover. Oracle Data Guard work on two database roles Primary and Standby. SWITCHOVER command, and the databases are managed by Oracle After a role change, the naming service can be updated with the new primary's address. If there is more than one standby database in the configuration, you must explicitly set the FastStartFailoverTarget property on the primary database to name one or more candidate target standby databases. After the restart, Redo Apply begins applying redo data from the new primary START OBSERVING [cfg_group_name] starts a new observer for each broker configuration in the specified group. are configured correctly. If provided, then each group needs to have at least one broker configuration declared in the second part. When the primary database and the target standby database regain network connectivity, the broker will disable fast-start failover for the entire broker configuration. After step 3 completes, you can open the new Primary database STAN: The observer automatically starts the reinstatement process. This brings up the General Properties page that provides a Reinstate button. SQL>select sequence#, applied from v$archived_log; Dataguard Configuration details:- Login in to Standby Server:- Step:1 Check the database role and open_mode Select name,open_mode,database_role from v$database; Step:2 Cancel the MRP process alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary The following sections describe how to reinstate or reenable a database. WAIT option, broker waits for the amount of STANDBY>ALTER DATABASE OPEN; Disable fast-start failover using the DGMGRL DISABLE FAST_START FAILOVER command. North_Sales is in the primary role. fast-start failover through Cloud Control. 2. Make some new changes and verify that they are preserved after failover. They must be re-created from a copy of the new primary database. 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. The commands that can be executed for a group of configurations (as declared in an observer configuration file) are as follows. In order to apply redo data to the standby database as soon as it is received, use Real-time apply. This action may result in two databases in the configuration simultaneously assuming the primary database role should fast-start failover occur. Careful consideration should be given before enabling fast-start failover for either of these conditions because doing so will supersede availability options provided by Oracle Clusterware. callout configuration scripts fsfo_precallout and Enabling fast-start failover and starting an observer process involves the following tasks. The default name of the callout configuration file is Enabling Fast-Start Failover describes how to start observers as a part of the step-by-step process to enable fast-start failover. Set the, Configure the connect descriptor with a single network name that is registered with a global naming service such as DNS or LDAP. once the target standby database's redo applied point is no longer lagging behind the primary During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. For example: Using DGMGRL, you can do this by examining the output of the SHOW CONFIGURATION LAG. Chapter 9 of the Data Guard Broker documentation (10g and 11g) contains a description of each property. Regardless of the method you choose, the broker coordinates the role transition on all databases in the configuration. What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. observer computer is returned to you so that you can continue to When a switchover is started, the primary and standby databases that are involved should have as small a redo lag as possible. By default, the observer will initiate failover to the target standby if and only if ALL of the following are true: Oracle Database 11g Rel 1 introduced user configurable failover conditions that can trigger the observer to initiate failover immediately. 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. It is then started and stopped on the primary database. PRIM>SHUTDOWN IMMEDIATE; So if the original Primary database is still accessible, you should always consider a switchover first. If the database is managed by Oracle Clusterware, broker does not open any pluggable The minimum value of ObserverPingInterval is 100 See Choosing a Target Standby Database for helpful advice. This section describes how to stay on top of your FSFO environments. To override this behavior and allow a fast-start failover to occur if the observer is unable to contact the primary for more than FastStartFailoverThreshold seconds, set the ObserverOverride property to TRUE. You can disable fast-start failover if necessary, by using the FORCE option. Broker will verify that the configuration meets all prerequisites before enabling FSFO and will report any problems it finds. Regards, Narottam Tagged: dataguard dba rac Welcome! Read-Only Standby and Active Data Guard Download Ebook Oracle 11g 12c Data Guard With Asm Lab Practice A Complete Hands On Lab Practice To Manage A Data Guard . It also requires Flashback Database to be enabled on both the primary and target standby databases. If possible, confirm that fast-start failover has not In the previous article, we have seen switching the role of Primary and standby database and failover Primary role to Standby database manually. configuration property specifies how frequently the observer The target standby database when it does not have connectivity with the primary database, fast-start failover is disabled only on the target standby database. Look for the desired data in the RAM. For instance, you could log into the system running observer1 to stop observer2. If both of those observers are unavailable, the observers Note: the FSFO observer version must match the database version. directory. The environment is a single instance database without any grid Infrastructure components. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. You can also specify a list of ORA- errors that will initiate FSFO failover. If you don't already have a Flash Recovery Area (FRA), you will need to create one for Flashback Database. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. Note: Many of the Broker database properties correspond to database spfile parameters. Use Recovery Manager (RMAN) to back up the PeopleSoft database on a regular backup schedule. Data Guard | Oracle After the fast-start failover completes successfully, the master observer will attempt to reinstate the former primary database as a new standby database when a connection to the former primary database is reestablished, and the FastStartFailoverAutoReinstate configuration property is set to TRUE. Connect-Time Failover to Standby Database - Ed Chen Logic How to Enable Fast-Start Failover in Oracle Data Guard They must be re-created from a copy of the new primary database. Bounce your database and verify database name its open mode and its role: SQL> shutdown immediate; ORA-01109: database not open Database dismounted. Set both these properties to achieve a primary failure detection time of 1 New sql server failover cluster installation greyed outtrabajos By default, the broker always determines whether bystander standby databases will be viable standby databases for the new primary when performing a complete failover. 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. You can switch back to the original Primary database later by performing another switch over. observer name, host, whether it is the master observer, when it became the master In this mode, the FastStartFailoverLagLimit configuration property is set to a non-zero value. If failover is not possible for some reason, then the master observer will continue checking whether the standby database is ready to fail over. [PATCH v5 0/6] Add Toshiba Visconti Video Input Interface driver To disable fast-start failover, use the Fast-Start Failover wizard in Cloud Control or the DGMGRL DISABLE FAST_START FAILOVER [FORCE] command. created when the START OBSERVER command is issued. cannot use a different name for this file. become the master observer. Clusterware: The broker notifies Oracle Clusterware to stop active After the conversion, the broker will start Redo Apply to apply accumulated redo data, before failing the database over to the primary role. times that the observer retries a failed ping before it initiates a What is true about Data Guard setup with fast-start failover? During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. For a system to process an instruction involving data access, these are the certain steps involved: Fetch the block of data from the hard disk (secondary/permanent storage) to the primary memory (e.g. Displays the current fast-start failover mode. There are many examples, and Ritesh Chhajer offers this example of doing a Data Guard switchover using dgmgrl: 1. Group definition this section is optional. upheld. To stop it, you can do either of the following: Choose the Stop Observer option on the first page of the fast-start failover wizard and click Continue at the bottom of the page. Guide to Oracle Data Guard Fast-Start Failover Initiate reinstatement by mounting the database. Any standby database that was disabled by the broker must be reinstated or re-created, as described in Reenabling Disabled Databases After a Role Change, before it can be a standby database for the new primary database. You might, for instance, use this to allow the observer to monitor the databases using the same connect identifiers as the client applications. Determines whether or not any standby databases that did not participate in the failover operation have applied redo data beyond the new primary database, and thus need to be disabled. 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. have received all the redo data the primary has generated in order for automatic failover to You must ensure that the primary database is shut down prior to performing a manual failover. Oracle recommends that this property be set to a value that is small enough to allow timely detection of faults at the primary database, but large enough to limit the overhead associated with periodic observer connections to an acceptable level. Oracle 11g Manual Data Guard Part-II - DBAtricksWorld.com Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option. Oracle Data Guard Manual Failover - ORACLEAGENT BLOG This feature enables RMAN to duplicate an existing database over the network without requiring a backup to disk or tape. When you configure data guard using OCI console, the default mode is set to maxprotection. 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. In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. fsfo_postcallout are stored in the same location as isolated. The drain_timeout is specified in the SRVCTL must create a .suc and .err file in the After a complete failover finishes, any bystander standby database that is not viable as a standby for the new primary database will be disabled by the broker. 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 this is an Oracle RAC physical standby database managed by Oracle Clusterware, then the broker directs Oracle Clusterware to restart the new standby database. Other logical standby bystander databases in the broker configuration will remain viable after the switchover. This exercises the configuration, but triggers failover differently than losing contact with the primary. These scripts must be in the same directory as the 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. STOP OBSERVING, and SET See Enabling Fast-Start Failover for more information. This is time, if all the sessions that are connected though the active services You must also start and stop the SALESRO service on the primary so that it can be started on the standby. Managed recovery process has been stopped between primary and standby database and standby becomes primary database. Moorestown, New Jersey, United States. 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. For example: Fast-start failover occurs if both the observer and the target standby database lose connection to the primary database for the period of time specified by the FastStartFailoverThreshold configuration property. A number of prerequisites must be met on the primary in order to use Fast-Start Failover. 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. Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. Note that role changes to logical standby databases always result in physical standby database bystanders being disabled. The name of the callout configuration file is fsfocallout.ora. To stop the observer when fast-start failover is enabled, the primary database and target standby database must be connected and communicating with each other. You can start the observer before or after you enable To achieve ConfigurationSimpleName represents After the broker receives the STOP OBSERVER request, the request is passed to the observer the next time the observer contacts the broker, and the observer then stops itself. If the observer is unable to regain a connection to the primary database within the specified time, then the observer begins a fast-start failover provided the standby database is ready to fail over. In an Oracle Data Guard configuration, the SRVCTL -startoption for a standby database is always set to OPEN after a switchover. The following sections describe how to perform manual failovers: Reenabling Disabled Databases After a Role Change. Cancel MRP process. 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; The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database.
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