The selected standby database that will be the fast-start failover target must receive redo directly from the primary database. In this case fast-start failover cannot occur because the databases are not ready to failover. Stores files related to the observer and callout configuration. database is in the primary role. All physical and snapshot standby databases will be disabled and must be re-created from a copy of the new primary database after a switchover to a logical standby database. The following is an example of setting the LogXptMode property: Alternatively, use the RedoRoutes property to set the redo transport mode for the target standby and database that is currently in the primary role. If the new primary database was a primary database in the past, and had block If fast-start failover is Whereas a switchover to a logical standby database will invalidate and disable all of the physical and snapshot standby databases in the configuration. You cannot create the standby DB system in a different AD from the primary DB system. However, failover is attempted if the ObserverOverride configuration property is set to TRUE. db_domain . directory. Configure Data Guard Broker to manage and monitor the Data Guard configuration. lag is less than or equal to the value specified by the file (fsfo.dat). Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. 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. Valid values are >= 100. Relationship Between Primary, Target Standby, and Observer During Fast-start Failover. observer computer is returned to you so that you can continue to Startup can fail with "ORA-16647: could not start more than one observer" even when no observer is actually running if the previous observer process terminated without deregistering itself and the new observer isn't using the previous fsfo.dat file. Set this property for the primary and target standby database if you want the observer to use a different connect identifier than that used to ship redo data (that is, the connect identifier specified by the DGConnectIdentifier property). The remaining observers are called backup observers. Expected output is shown in blue text. 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 failover is not possible for some reason, then the master observer will continue checking whether the standby database is ready to fail over. In order for Flashback Database to succeed, there must be sufficient history available in the Flashback Database logs and all of the redo generated between the restore point and the standby_became_primary_scn must be available. The environment is a single instance database without any grid Infrastructure components. To maximize the benefits of FSFO, the observer should run on a different host than the primary and standby databases. For the RMAN duplicate active database method, the init.ora file (initdb1.ora in the example) requires only one parameter: db_name (it doesn't even have to be the real name of the database - any name will do). Disable fast-start failover using the DGMGRL DISABLE FAST_START FAILOVER command. Overall commit latency is increased by the round-trip network latency. You must use the Oracle wallet to store the credentials for all broker configurations to be managed. When you configure data guard using OCI console, the default mode is set to maxprotection. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. required permissions, the admin folder is created This means that in order for a flashback database operation to succeed, observer and the standby both lose contact with the primary. Each database in a Data Guard configuration must have a unique name. You can query the V$DATABASE view to verify that the observer is started and the configuration is ready for fast-start failover. 1. This walkthrough assumes that all ORLs and SRLs on the primary and standby databases are the same size. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. After Fast-Start Failover: The fast-start failover has completed and the target standby database is running in the primary database role. This example shows the verbose mode of the 'show configuration' command that provides FSFO-specific information. PeopleSoft can be configured for Active Data Guard. If the primary database has multiple standby databases, then you can specify multiple fast-start failover targets, using the FastStartFailoverTarget property. 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). 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. Once an observer is started, no further user interaction is required. This 5. Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_DG package. Stop the observer using the DGMGRL STOP OBSERVER command. This section describes how to stay on top of your FSFO environments. second. You cannot create the standby DB system in a different AD from the primary DB system. For more details about managing Redo Apply services using properties, see Managing Log Apply Services. operation. alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. To start an observer as a background process, use the DGMGRL switch does not happen until the next time the primary contacts the target standby, Conditions shown in blue are enabled by default. This may take a few minutes. When using DGMGRL, you need to issue the SWITCHOVER command, specifying the name of the standby database that you want to change into the primary role. After step 3 completes, you can open the new Primary database STAN: If a fast-start failover was initiated because the primary database had crashed or lost connectivity with the master observer and target standby database, then the master observer automatically attempts to reinstate the former primary database as a standby database, if the FastStartFailoverAutoReinstate configuration property is set to TRUE. This action will result in loss of data and the possibility of two databases in the configuration simultaneously assuming the primary database role. 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. When the primary database and the (non-target) standby database regain network connectivity, the broker will propagate its current fast-start failover setting (ENABLED or DISABLED) to the non-target standby. Oracle Data Guard Broker is a utility that can help you manage your Oracle Data Guard. Dataguard broker is used to automate monitoring and controlling standby setups. Observers continuously monitor the fast-start failover environment to ensure the primary database is available (described in When Fast-Start Failover Is Enabled and the Observer Is Running). If the primary and target standby databases do not have network connectivity or if the database to which you are connected does not have network connectivity with the primary database, consider using DISABLE FAST_START FAILOVER with the FORCE option. SET ObserverConfigFile used to specify a customized observer configuration file. Indexing is a mechanism by which the underlying data is mapped for faster retrieval. In maximum protection mode, an automatic failover is always possible because the maximum availability and maximum performance modes, to avoid a Simply use DISABLE FAST_START FAILOVER. The following paragraphs describe the supported availability modes. Follow the guidelines described in Choosing a Target Standby Database. Then, on the Fast-Start Failover Change Mode page, click Enabled. Perform SWITCH LOGFILE if necessary. What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. The Oracle Database 10g FSFO observer is limited to using the default username and password defined in the wallet. If it's not, DGB will not allow the failover to continue until the DBA has manually resolved any discrepancies. fast-start failover. 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. Additionally, the new master observer is identified in the output shown for the SHOW FAST_START FAILOVER and SHOW OBSERVER commands. FastStartFailoverLagLimit configuration property. Note that primary and standby databases must be licensed for Oracle RAC or Oracle Active Data Guard in order to use Application Continuity. 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. If the database is not managed by Oracle Clusterware, Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. . 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. For each temporary table, verifying that temporary files associated with that table on the primary database also exist on the standby database. Note: Data Guard requires dedicated server connections for proper operation. pre-callout configuration script and post-callout configuration script. Set the ObserverPingInterval and If fast-start failover is initiated, the master observer verifies the target standby database is ready to fail over to the primary database role. Create a unique connect alias for each database. The following steps all require the database to be in a mounted (not open) state. You can disable fast-start failover if necessary, by using the FORCE option. Testing FSFO failover requires simulating loss of the primary. Disabling fast-start failover with the FORCE option when connected to the target standby database guarantees that fast-start failover will not occur. For example: You can find information about the master observer by querying the V$DATABASE view. If the observer is stopped abnormally (for example, by typing CTRL/C), restart it and reference the existing fsfo.dat file with the FILE IS qualifier. To start an observer, you must be able to log in to DGMGRL with an account that has If Flashback Database history is insufficient, the observer will not be able to reinstate and you will have to manually reinstate from backup or by primary duplication. Enable Active Data Guard for read-only workloads. 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. If clients are already configured to automatically time out and reconnect if they don't get a response from the database, a simple but effective approach is to use a network alias (e.g. 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. Attempt to open the primary database, or the following error may be returned: This error may return if the fast-start failover validity check fails or does not complete in under two minutes. If the client uses remote ONS subscription, the client must specify the hostname and port of the ONS daemon(s) of the primary database and each standby database. To verify this change, again query the Database_role column of V$DATABASE. When performing a switchover in a configuration whose standby databases are Such preparation includes: Ensuring that standby redo log files are configured on the primary database. Let's run the command on the primary database to validate if the environments are ready for the role transition : JITPRD> alter database switchover to JITSDB verify; alter database switchover to JITSDB verify * ERROR at line 1: ORA-16475: succeeded with warnings, check alert log for more details The example below takes advantage of the 11g RMAN Active Database Duplication feature. A failover may or may not result in data loss depending on the protection mode in effect at the time of the failover. If the configured data loss guarantee cannot be upheld, The master observer cannot connect to the target standby database, What Happens if the Observer Fails? If necessary, you can shut down the primary or target standby database in a fast-start failover environment. The target standby database has contact with the primary database. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. To get started, all you'll need is Oracle Database Enterprise Edition Release 10.2 or later, a database, and three hosts: two for the databases and a small host for the FSFO observer. To use a far sync instance with fast-start failover, the far sync instance transport mode must be set to either SYNC or FASTSYNC and the target standby database transport mode must be set to ASYNC. If no value is specified for the Make some new changes and verify that they are preserved after failover. Do this prior to every failover test. Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring FAN, FCF, and ONS on an Oracle Real Application Clusters (Oracle RAC) database. Table 6-2 FS_FAILOVER_STATUS Column of the V$DATABASE View. Note: You can also use TNS aliases defined in the tnsnames.ora file when setting the local_listener parameter. If you are performing an immediate failover, then the database role is changed to primary without applying any accumulated redo data. If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. Worked as a Development and Database Administrator. The terminal session will appear to hang at this point. The example uses the FROM ACTIVE DATABASE clause introduced in 11g that allows RMAN to create a standby database by copying the primary across the network without the need to store the backup files on disk or tape. The advanced way is in the following article: Connect-Time Failover by a Dynamic Service Name. In a DataGuard environment when the Primary instance fails you need to go through the Failover and Reinstate processes in order to restore the database service, as described in the documentation: Changes a standby database to the primary role in response to a primary database failure. 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. configuration property. After FSFO is enabled, Broker will continue to check that Flashback Database is enabled during health checks. SQL> Select Database_role from v$Database; Whenever possible, you should switch over to a physical standby database: If the switchover transitions a physical standby database to the primary role, then: The original primary database will be switched to a physical standby role. Determines whether or not any standby databases that did not participate in the failover operation have applied redo data beyond the new primary database, and thus need to be disabled. Oracle Data Guard can switch a standby database to the primary role in case a production database becomes unavailable due to . You will have to reinstate or re-create (see Reenabling Disabled Databases After a Role Change) the standby databases after failover has completed. The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. standby database, host, or network failure, etc.). The syntax for the optional definition of a broker configuration group is: The group definition section is optional. The old Primary must have been running in flashback mode before the failover. It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. To avoid problems due to timing variations, values less than 60 minutes are not recommended and values of 30 or less virtually guarantee Flashback Database failure. Note: Many of the Broker database properties correspond to database spfile parameters. add service command. you need to make the primary database available, first confirm that a The SQL> Select Database_role from v$Database; The observer does not attempt to reinstate the former primary database. It must appear as the first part of an observer configuration file. The FORCE option disables fast-start failover on the database to which you are connected even when errors occur. You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. But it will also continue trying to reconnect to the primary database indefinitely. It is then configured to be active in the PHYSICAL_STANDBY role on the physical standby database SOUTH. 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. 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 For this build, we will use a single physical standby database. primary database must have network connectivity. Oracle Data Guard is a solution provider to businesses by offering data protection and its disaster recovery along with its high availability. drain_timeout amongst the active services. 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. 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. The former primary database is disabled. If automatic reinstatement fails, the broker will log errors and the former primary database will remain in the mounted state. You can switch back to the original Primary database later by performing another switch over. If the primary database is an Oracle Real Application Clusters (Oracle RAC) database, the master observer will attempt to connect to one of the remaining primary instances. RAM). Use the SQL ALTER DATABASE MOVE DATAFILE command to rename or relocate an online data file on a physical standby that is a fast-start failover target if the standby is mounted, but not open. If you performed a failover or switchover that requires you to re-create the failed primary database or standby databases that were disabled during the role transition, then follow the procedures in the Oracle Data Guard Concepts and Administration chapter, "Creating a Physical Standby Database" and also the Oracle Data Guard Concepts and Administration chapter, "Creating a Logical Standby Database.". environment variable must have exclusive permissions wherein it can be accessed only The broker disables all of the physical and snapshot standby databases in the configuration. The target standby database is enabled and is in the APPLY-ON state. To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . It's good practice to use separate listeners for application connections and Data Guard connections. Reinstatement is supported only after failover in a broker configuration. As mentioned above, Maximum Availability mode is mandatory for Oracle Database 10g and optional for Oracle Database 11g. However, you do have the option of specifying a name and location for the observer configuration file. They must be re-created before they can serve as standby to the new primary database. Although the default value of 30 seconds is typically adequate for detecting outages and failures on most configurations, you can adjust failover sensitivity with this property to decrease the probability of false failovers in a temporarily unstable environment. The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. fast-start failover, you can issue the DGMGRL SHOW FAST_START FAILOVER, A high lag limit may lead to more data loss but may lessen the performance impact of the primary database. time, if all the sessions that are connected though the active services configuration named ConfigurationSimpleName. It is instructive to watch the alert logs on both databases as well as the observer log after aborting the primary to gain insight into what happens during FSFO failover. In this case, the FS_FAILOVER_STATUS and FS_FAILOVER_OBSERVER_PRESENT columns will appear as shown in the following table and fast-start failover will not occur: Oracle Database Reference for more information about the V$DATABASE view. 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.
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Retirement Clearinghouse Legit, Keller Williams Operating Principal Job Description, Articles D