data guard failover steps data guard failover steps

Disabling fast-start failover without the FORCE option can succeed only if the database on which the command is issued has a network connection with the primary database and if the primary database and target standby database have a network connection. Reconnect within the time specified by the FastStartFailoverThreshold property. The foundation of FSFO is Data Guard - a primary and at least one standby. Note that the new primary database does not need to be restarted. Ensure that the required permissions are granted to the DG_ADMIN Issue the following commands on Primary database and Standby database to find out: This lets you take advantage of the broker's You cannot create the standby DB system in a different AD from the primary DB system. Then the STOP OBSERVER command can be issued successfully on the former master observer. guaranteed to lose no data. The services include switchover, switchback and failover. Starting with 10.2.0.4 (including all versions of 11g and later), Oracle provides the FastStartFailoverPmyShutdown Broker property that allows you to specify what the primary should do if it is still in a stalled state when the FSFO threshold timeout has elapsed. Set the FastStartFailoverThreshold property to specify the number of seconds you want the observer and target standby database to wait (after detecting the primary database is unavailable) before initiating a failover. second. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. When you configure data guard using OCI console, the default mode is set to maxprotection. The FastStartFailoverLagLimit configuration property is only used by the broker when enabling fast-start failover for configurations operating in maximum performance mode. In maximum protection mode, an automatic failover is always possible because the database's redo generation point by more than the value specified by the Disaster Recovery with Oracle Data Guard - online presentation To start a switchover using Cloud Control, select the standby database that you want to change to the primary role and click Switchover. Switches roles between the primary and standby databases. you need to make the primary database available, first confirm that a The observe-only mode for fast-start failover enables you to test how fast-start failover will work in your environment. A switchover to a physical standby database is preferable because all databases in the configuration will be available as standby databases to the new primary database after the switchover operation completes. Note the following points about the observe-only mode: The primary database can enter UNSYNC or LAGGING state without an acknowledgement from the observer or target standby. Choose a value high enough to avoid false disconnects from intermittent network trouble. configuration file, such as START OBSERVING, observer on ob1-host will be given priority over Failing over the database won't do much good if applications and other database clients don't know where the primary went. 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 this case, Flashback Database cannot be used to reinstate databases. standby database is mounted, broker remembers this setting. Note: if the observer loses contact with the primary, but the standby does not, the observer can determine that the primary is still up via the standby. If the master observer detects an availability problem with the primary database, then it typically attempts to reconnect to the primary database within the time specified by the FastStartFailoverThreshold configuration property. Fast-start failover can be used only in a broker configuration and can be configured only through DGMGRL or Cloud Control. Reset database properties related to Redo Apply services, such as DelayMins. While Oracle 11g's Data Guard definitely protects a database when the entire production site is lost via its failover capabilities, it's still necessary for an Oracle DBA to intervene to complete the failover process. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. Now it will return PRIMARY. SQL> Select Database_role from v$Database; If the database is managed by Oracle Clusterware, broker does not open any pluggable The pre-callout script If there is only one observer, then it is considered to be the master observer. If it reconnects to the primary database before the standby agrees to fail over, then the master observer will stop attempting to initiate a fast-start failover. 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. The master observer cannot connect to the target standby database, What Happens if the Observer Fails? 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. Note: If you have just enabled archivelog mode, force an archive log creation ( alter system archive log current) to ensure that at least one archive log exists. Issue the following SRVCTL commands so that both databases in the Data Guard configuration know about the two potential services for each database: To start things up initially, you must manually start the services on the right node. Note that a switchover operation may be started before the specified wait (Note that the target standby cannot be a far-sync instance. More specifically, we can have an asynchronous second read-only Managed instance in the same or in a different region. The primary and target standby must have connectivity for the STOP OBSERVER command to complete successfully. Broker stores it configuration information in a mirrored set of files outside the database. If you don't already have a Flash Recovery Area (FRA), you will need to create one for Flashback Database. POTENTIAL DATA LOSS: Fast-start failover is enabled with some data loss. The master observer uses the value specified by either the DGConnectIdentifier or ObserverConnectIdentifier database properties to connect to the primary and fast-start failover target standby databases. In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. There can be up to four If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. Have a means of notifying someone if standby apply falls too far behind. We could not find a match for your search. Oracle 11g Physical standby data Guard Failover steps - Data Guard Part Learn how your comment data is processed. Note the use of "/@" to login using the wallet. Stop the observer using the DGMGRL STOP OBSERVER command. Reinstatement restores high availability to the broker configuration so that, in the event of a failure of the new primary database, another fast-start failover can occur. 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. Example 6-2 Sample Observer Configuration File. an alias of the broker configuration name. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. lower detection times for primary database failures, you must The word manual is used to contrast this type of failover with a fast-start failover (described in Fast-Start Failover). Use Broker's "show configuration" command to determine FSFO status and the "show database statusreport" command to drill down for details if Broker reports a problem. See Setting the Protection Mode for Your Configuration. SQL>connect /@STAN as sysdba If fast-start failover is enabled, then a switchover can be performed only to the pre-specified target standby database and only if the standby database is synchronized with the primary database or is within the configured lag limit, for the max availability and max performance modes respectively. The minimum allowable limit is 10 seconds. Before enabling fast-start failover, use one of the following techniques Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. 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. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . We will create 4 SRLs starting with group# 11. Check the spelling of your keyword search. It is also possible to initiate failover using the dgmgrl failover command. Use the oraenv script provided by Oracle. Use the SHOW CONFIGURATION BystandersFollowRoleChange command to see the value of this property. In order to apply redo data to the standby database as soon as it is received, use Real-time apply. RMAN will copy the spfile from the primary, so this init.ora file is only needed during the first phase of the duplication. After setting local_listener, register the database with the listener and verify the services have been registered. The default Make sure that your OS environment on the standby is setup. Fast-Start Failover allows Data Guard to automatically failover to a previously chosen standby database without requiring manual intervention to invoke the failover. Starting with 11 is purely cosmetic - it allows new ORL groups to be added later while keeping their group# in the same sequence as the existing ORLs. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). The DB_ROLE_CHANGE event will fire whenever a database is opened for the first time after a role transition. The same process should work for RAC environment as my colleague has . Your email address will not be published. Metadata for the fuzzy snapshot is stored in the flashback log itself. Data Guard uses Oracle Net (SQL*Net) for communication between the primary and standby databases and the FSFO observer. If fast-start failover is disabled, then manual failover may still be possible. 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. The commands that can be executed for a group of configurations (as declared in an observer configuration file) are as follows. How we create a failover group in Azure Managed Instance The broker never automatically reinstates the former primary database if a fast-start failover was initiated because a user configuration condition was detected or was requested by an application calling the DBMS_DG.INITIATE_FS_FAILOVER function. You can specify STOP OBSERVER ALL to stop all observers registered in a broker configuration. 1. Fast-start failover is faster when you take steps to optimize recovery so that the application of redo data to the standby database is kept up to date with the primary database's rate of redo application. 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. The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database. Then, click Continue to proceed to the next page. This list describes restrictions when fast-start failover is enabled. How To Configure Client Failover For Data Guard Connections - Oracle Flashback Database stores its logs in the Flash Recovery Area (FRA), so the FRA must be large enough to store at least 60 minutes of Flashback Database history. this script is run before the fast-start failover is initiated. To switchover to a standby that is not the current failover target: John Smiley [jrsmiley@gmail.com] is a persistent storage architect for a major online retailer. There is little risk in enabling Flashback Database to determine its storage requirements - it can be disabled while the primary is open if necessary. DGMGRL can be used to manage multiple observers in a group of broker configurations. directory by this environment variable does not exist, or the $DG_ADMIN . Step:1 Check the database role and open_mode If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. Application calls to DBMS_DG.INITIATE_FS_FAILOVER. This results in the observer establishing a new connection to the primary database every 30 seconds. If the designated fast-start failover target develops a problem and cannot be the target of a failover, then the broker automatically changes the fast-start failover target to one of the other candidate targets. The example uses the FROM ACTIVE DATABASE clause introduced in 11g that allows RMAN to create a standby database by copying the primary across the network without the need to store the backup files on disk or tape. Getting the Oracle Net configuration right is one of the key factors in a successful FSFO deployment. In the previous article, we have seen switching the role of Primary and standby database and failover Primary role to Standby database manually. But it will also continue trying to reconnect to the primary database indefinitely. client-side broker files, the specified values are used. The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. The command SHOW OBSERVER provides detailed information about registered observers. You must then re-create it from a copy of the new primary database and reenable it as described in How to Re-create and Reenable a Disabled Database. there is a lost network connection, be aware that the observer may attempt a For switchovers, understanding all of the factors can simplify the choice of which standby database to consider as your new primary database. SQL> Select Database_role from v$Database; Hi, I am working in IT industry with having more than 10 year of experience, worked as an Oracle DBA with a Company and handling different databases like Oracle, SQL Server , DB2 etc The broker first converts the original primary database to run in the standby role. PRIM>STARTUP MOUNT; See FastStartFailoverTarget for more information about this property. 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. This is typically done for planned maintenance of the primary system. If the They rely on Oracle Data Guard for high availability databases, with a standby database running in a different availability zone. 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 default name of the observer runtime data file is The following example shows you how to set up more than one service on a database and how using the broker ensures that the correct service starts on the correct database. Starting the Observer Using Cloud Control. Be sure to include the Data Guard listener in the local_listeners database parameter. What is true about Data Guard setup with fast-start failover? In a Data Guard environment primary database is open in read write mode and the standby database in read only mode for reporting purpose. database (if real-time query is enabled). Monitor the environment to ensure the primary database is available. This can happen for either of the following reasons: A bystander standby database has applied more redo data than the new primary database itself had applied when it was a standby database. The default name of the callout configuration file is In Oracle Database 11g, the password file on the standby must be a physical copy of the password file on the primary due to security enhancements introduced in Oracle Database 11g. Oracle Data Guard configuration with DGMGRL. Notice that the terminal session appears to hang after starting the observer. 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. Broker maintains these parameters by issuing ALTER SYSTEM commands as appropriate during role transitions, database startup/shutdown, and other events. ensure that it has the required permissions. See Oracle Enterprise Manager Command Line Interface. We'll start with switchovers. It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. configuration file Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. Therefore, the primary database can continue processing transactions, even if the target standby database fails. 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$DATABASE view. If Flashback Database fails, automatic reinstatement stops and you will have to perform a manual SCN-based recovery to the standby_became_primary_scn and complete the reinstatement. failover configuration file, this script is run. A failover to a logical standby database requires that all physical and snapshot standby databases be re-created from a copy of the new primary database after the failover completes. The target standby database has contact with the primary database. fast-start failover through Cloud Control. A failover is a role transition in which one of the standby databases is transitioned to the primary role after the primary database (all instances in the case of an Oracle RAC database) fails or has become unreachable. To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. 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. Complete Failovers in Configurations Using Far Sync Instances. Starting with Oracle Database Release 21c, use the DG_ADMIN The broker preserves the protection mode that was in effect prior to the failover. Choosing a Target Standby Database for Switchover and Choosing a Target Standby Database for Failover provide guidelines to help you choose a target standby database. For reliable startup, the initial connection should always be made to the primary. By default the file is named fsfo.dat and is created in the working directory where the observer is started. The environment is a single instance database without any grid Infrastructure components. observer. Is possible if the target standby database displays SYNCHRONIZED and the FS_FAILOVER_OBSERVER_PRESENT column displays YES. The ObserverPingInterval Credentials Required for Access to Broker Configurations. Enable Active Data Guard for read-only workloads. Flashback Database records the before-image of changed blocks. Start the observer by running dgmgrl and logging in using SYS credentials. This table describes the optional database properties that you can set. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: PRIM>connect /@PRIM as sysdba The observer automatically starts the reinstatement process. All database connections associated with the observer, including the initial connection, must use dedicated server connections. You can switch back to the original primary and then either retry the switchover to the original target standby, or choose another standby in the configuration to switch over to. ObserverPingRetry configuration properties. 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. 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. If you initiated a complete failover and it fails, you might need to use immediate failover. Ensure SPFILE is used SQL> sho parameter spfile 2. These Failover:- 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. This nomination is noted in the observer log file and in the broker log file (drc*.log). FSFO can also be used with logical standbys and an FSFO-enabled configuration may have multiple standbys with a mix of physical and logical, but only one standby can be the failover target at any given time. environment that is guaranteed to either lose no data (when the 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. This support note is available at http://support.oracle.com. Oracle Data Guard provides the ability to create and maintain Standby databases at one or more sites These protect Oracle databases from database and server failures as well as site disasters Failover to one of the alternate sites can be set to happen automatically (fast-start failover) or manually if the primary database is not usable 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. 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. 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. Whether or not standby databases that were not the target of failover (bystander standby databases) are disabled depends upon how much redo data they have applied relative to the failover target and the standby type of the failover target: If the failover target is a physical or snapshot standby database, the original primary database must be reinstated or re-created in order to be a standby database for the new primary database. 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/. Restarts the new standby (former primary) database if the switchover occurs to a physical standby database, and Redo Apply begins applying redo data from the new primary database. observers for a single Data Guard configuration. 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. Make sure that xdpyinfo exist under PATH variable. Bystander standby databases that are not disabled by the broker after the switchover will continue operating in the state they were in before the switchover. They must be re-created from a copy of the new primary database. Otherwise, they must be re-created from a copy of the new primary database. file (fsfo.dat). . Step:6 Create or update the fast-start failover callout configuration file and include The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. Controlfile is permanently damaged because of a disk failure. Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. You have done a failover to your Standby database so it becomes the new Primary. When the primary database and the target standby database regain network connectivity, the broker will disable fast-start failover for the entire broker configuration. STOP OBSERVING, and SET FS_FAILOVER_OBSERVER_HOST shows the name of the computer on which the master observer is running, FS_FAILOVER_OBSERVER_PRESENT shows whether or not the master observer is connected to the local database. It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). If the protection mode was at maximum availability or maximum performance, it remains unchanged. The Oracle Database 10g FSFO observer is limited to using the default username and password defined in the wallet. It will also alert you to databases that have had Flashback Database disabled at some point after FSFO was enabled. Observer sites monitor the fast-start failover environment. It automatically recovers the maximum amount of redo data for the protection mode the configuration is operating in. November 20, 2009. The FORCE option disables fast-start failover on the database to which you are connected even when errors occur. 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". The connect descriptor must contain the SERVICE_NAME parameter in either case. See Reenabling Disabled Databases After a Role Change for more information. The new primary database is opened in read/write mode and redo transport services are started. Steps to Create a Physical Standby Databa se 3 -3 Preparing the Primary Database 3 -4 FORCE LOGGING . When this command is issued, the actual 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. It provides a way to quickly restore a database to a previous point in time or SCN using on-disk data structures called flashback logs. The broker allows an immediate failover to proceed even if there are errors present on the standby database that you selected to participate in the failover. However, if the standby has had contact from the primary within the period of time specified by the FastStartFailoverThreshold property, the standby prevents the failover attempt. Failovers become routine. Oracle Data Guard 11gR2 Administration : Beginner's Guide