data guard failover steps data guard failover steps

When a fast-start failover occurs because either a user configurable fast-start failover condition is detected or an application initiates a fast-start failover by calling the DBMS_DG.INITIATE_FS_FAILOVER function, the former primary database is always shut down and never automatically reinstated. Now your old standby database is become primary database, it is highly recommended to consider immediate full backup of primary database. The VALIDATE FAST_START FAILOVER command can be used to validate a fast-start failover configuration and identify misconfigurations that prevent the initiation of fast-start failover. This action may result in two databases in the configuration simultaneously assuming the primary database role. Switching over to a logical standby database results in the snapshot and physical standby databases in the broker configuration being disabled by the broker, making these databases no longer viable as standby databases. ORACLE instance shut down. For example, perform full level 0 backups weekly and incremental level 1 backups daily. To stop the observer when fast-start failover is disabled, the primary database must be running. STANDBY> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; 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. STANDBY>connect /@STAN as sysdba observer and the others are backup observers. If any errors occur during either conversion, the broker stops the switchover. When you start a switchover, the broker verifies that at least one standby database, including the primary database that is about to be transitioned to the standby role, is configured to support the overall protection mode (maximum protection, maximum availability, or maximum performance) after the switchover is completed. Stores files related to the observer and callout configuration. select name,open_mode,database_role from v$database; Note: 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. Commit latency is not affected by redo transfer, but committed transactions whose redo has not been received by the standby will be lost during failover. 3. 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. Archiver is unable to archive a redo log because the device is full or unavailable. Note: Many of the Broker database properties correspond to database spfile parameters. There can be up to four observers for a single Data Guard configuration. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. However, failover is attempted if the ObserverOverride configuration property is set to TRUE. Use the 'show fast_start failover' command to see which user configurable FSFO failover conditions are in effect. This database property is used to specify how the observer should connect to and monitor the primary and standby database. You must manually re-create the database as a standby database and then reenable it. The only exception to this is failovers to snapshot standby databases. Learn how your comment data is processed. How to Test Data Guard Fast-Start Failover by Shutting Down Primary FastStartFailoverLagLimit property. fast-start failover has not occurred to the target standby database. Suppose you have a primary database, BOSTON, and a standby database, CHICAGO. created when the START OBSERVER command is issued. To achieve It will return PRIMARY, 2. 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/. To reenable broker management of these databases, you must reinstate or re-create the databases using one of the following procedures: If a database can be reinstated, the database will show the following status: Reinstate the database using the DGMGRL REINSTATE DATABASE command or the reinstate option in Cloud Control, as described in How to Reinstate a Database. The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. Oracle 12c-Step by Step Manual Data Guard Failover If the target standby database is a snapshot standby database, all of its instances must be restarted to the mount mode before performing failover. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. In short, the failover is the deformation of the production (primary) database and activating standby database as the primary. The other configurations that are not required but they might make your fast-start failover go smoothly. Now test FSFO failover back to the original primary. Bystander standby databases can be shut down at any time in any order without impacting fast-start failover. An existing connection which is already closed from the database side would throw an error. If the configuration is not failable, the DBMS_DG.INITIATE_FS_FAILOVER function returns an ORA error number (it does not signal an exception) informing the caller that a fast-start failover could not be performed. If the FastStartFailoverPmyShutdown configuration property is set to TRUE, then the former primary database will have been automatically shut down and must be manually restarted before the master observer can attempt to reinstate it. 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 Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. broker does not allow the primary database to commit transactions until it has regained For example, if a physical standby database was in the APPLY-OFF state, it will remain in the APPLY-OFF state. 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. 1. In order to fully automate switchover, Broker needs SYSDBA credentials in order to restart one or both databases. If the currently configured mode is maximum protection, Cloud Control will downgrade the mode to maximum availability. If possible, confirm that fast-start failover has not (It is permissible to change the RedoRoutes property on all standby databases including target standby databases. Note: this state also occurs on the primary during startup when fast-start failover is possible and neither the target standby database nor the observer are present to confirm it is okay to continue opening the database. Improper Oracle Net configuration is a leading cause of reported FSFO issues. times that the observer retries a failed ping before it initiates a In maximum availability mode, set the LogXptMode database property for both the primary and target standby databases to SYNC or FASTSYNC. Data Guard. For Maximum Availability environments, change this to synchronous. groups used by multiple configuration commands. 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. When running the START But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). Step-by-step instructions for manual reinstatement are described in Reenabling Disabled Databases After a Role Change. configuration. 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). If this occurs, run 'stop observer' and try again. You want to prevent fast-start failover from occurring because the primary database will resume service soon. Create a script to automate FSFO failover initiation and use it as your standard method for standby flips. The standby VM (myVM2) has the Oracle software installed only. file (fsfo.dat). Fast-start failover quickly and reliably fails over the target standby database to the primary database role, without requiring you to perform any manual steps to invoke the failover. The broker selects a target standby based on the order they are specified in the property. In this case, only observers on ob1-host and The subcommands for this verb include start, stop, setMaster, show, and delete_alternate_observer. If these parameters are modified outside of Broker, it raises a warning. Es gratis registrarse y presentar tus propuestas laborales. This nomination is noted in the observer log file and in the broker log file (drc*.log). The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database. Reinstate the former primary database as a new standby database. This section lists the steps the master observer takes to determine if a fast-start failover is needed and then to perform one, if necessary. See Setting the Protection Mode for Your Configuration. orapwd file=$ORACLE_HOME/dbs/orapw$ORACLE_SID. It is then started and stopped on the primary database. In this case, Flashback Database cannot be used to reinstate databases. failure on the primary database. all of the same type (all physical or all logical standby databases), choose the standby Group definition this section is optional. The failed primary database requires reinstatement as a new standby database to the new primary. Broker will validate the configuration, set parameters on both databases, and start managed recovery. Example 6-2 Sample Observer Configuration File. Broker will verify that the configuration meets all prerequisites before enabling FSFO and will report any problems it finds. 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. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. 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. The primary and target standby must have connectivity for the STOP OBSERVER command to complete successfully. Verifies that the primary and the target standby databases are in the following states: The primary database is enabled and is in the TRANSPORT-ON state. from another DGMGRL session. The default value is ALL. Ensure this file cannot be read by unauthorized users. 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. automatic failover feature in configurations set up for zero data loss protection at any observer on ob1-host will be given priority over WAIT option, broker waits for the amount of It uses these databases as a copy of the . Disabling fast-start failover with the FORCE option when connected to the target standby database guarantees that fast-start failover will not occur. Figure 6-2 The Observer in the Fast-Start Failover Environment. fsfocallout.ora and they have the required permissions. standby database is mounted, broker remembers this setting. If all the databases do not have the same values, SRVCTL attempts to override the values, which will fail on the physical standby database because it is open read-only. Immediate: No additional data is applied on the standby database, resulting in a data-loss . It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. It will not be allowed to open in any event if fast-start failover is enabled. Verify the configuration from both hosts. observer is still in contact with the standby. Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. There are normally two situations when this operation will be performed: a planned outage for maintenance of the primary database or disaster recovery. 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. 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. Staff support, hardware and software, security (both software and site), network connections, and bandwidth should be equivalent at both sites. configuration property specifies how frequently the observer The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . The old Primary must have been running in flashback mode before the failover. Make sure everything is working before moving on. isolated. If the service has been configured to start automatically (-policy AUTOMATIC), then the service will automatically start only after a database role change. fast-start failover succeeds, if a post-callout script is specified in the fast-start STOP OBSERVING [cfg_group_name] stops LOCAL observers running on this host (where this DGMGRL is running) for all broker configurations in a specified group. Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. 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. You must determine which available standby databases should be targets for failover. Queries and DML will continue to run - only sessions that commit will block. Opens the new primary database in read/write mode. Starting Observers as Background Processes. The playground: If both the observer and designated standby database lose connectivity with the primary database for longer than the number of seconds specified by the FastStartFailoverThreshold configuration property, the observer will initiate a fast-start failover to the standby database. Oracle Database 10g databases running versions prior to 10.2.0.4 will remain in a stalled state until aborted or signaled to remain the primary by the observer once connectivity has been restored. This file contains connect identifiers to both the primary and the target standby databases. When a switchover is started, the primary and standby databases that are involved should have as small a redo lag as possible. There is no impact on your current configuration or on applications. Using the db_unique_name of each database as the Oracle Net alias is simple and intuitive. An application should use caution when calling the DBMS_DG.INITIATE_FS_FAILOVER function because the observer will initiate failover, if at all possible. The time interval starts when the observer first loses its connection to the primary database. If the status is SUCCESS, you're ready to start testing role transitions. time specified by maximum configured Read-Only Standby and Active Data Guard This action will result in loss of data and the possibility of two databases in the configuration simultaneously assuming the primary database role. property. It is not reversible. Unless action is taken to change the failover target to one of the bystanders, the new primary will be without a failover target until the former primary is reinstated as a standby. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. Overview of Switchover and Failover in a Broker Environment. It's a good idea to have at least two hosts configured to run observers so that one can take over if the other fails. Make sure that your OS environment on the standby is setup. Now let's test switchover in the other direction. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. Reinstating the Former Primary Database in the Broker Configuration for more information about reinstatement. This is normal. Each observer has its own log file. (Note: 11.1.0.7 adds the StaticConnectIdentifier Broker database property to allow you to specify a different service name.) Fast-start failover enables the Data Guard broker to rapidly and automatically failover to a previously chosen standby database without requiring manual intervention. They can all be done at the same time in a single bounce. If the DG_ADMIN environment variable is not set, or the To start an observer as a background process, use the DGMGRL The syntax for the configuration declaration is: The definition for each broker configuration is: The configuration-name can be different from the name defined in the metadata of the Data Guard Broker configuration. See the Oracle Reference and Data Guard Administrator guides for your release for details. fsfo_postcallout are stored in the same location as Rather, fast-start failover will be enabled in accordance with the current protection mode. How to reinstate the old Primary as a Standby after Failover in #Oracle Verify the primary database instance is open. So if the original Primary database is still accessible, you should always consider a switchover first. 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. Such preparation includes: Ensuring that standby redo log files are configured on the primary database. The default DGConnectIdentifier, "Scenario 9: Performing a Switchover Operation" for an example of using the VALIDATE DATABASE command to show a database's readiness to complete a role switchover, "Scenario 10: Performing a Manual Failover Operation" for an example of using the VALIDATE DATABASE command to show a database's readiness to complete a role failover. The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. To stop an observer currently designated as the master observer, first issue the SET MASTEROBSERVER command to designate a different observer as master observer. 3. Implement Oracle Data Guard on an Azure Linux virtual machine If you will be using RMAN to create the standby database, it also needs a static service to restart the database being created. observer name, host, whether it is the master observer, when it became the master 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. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . A database in the primary role will not open until it has verified with the observer that it is still the primary. This property allows you to specify a priority ordered As shown in the table, fast-start failover can be enabled in maximum availability If the observer finds that the database is no longer the primary, it will attempt to reinstate it as the failover target standby. Then, click Continue to proceed to the next page. . Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. You can specify STOP OBSERVER ALL to stop all observers registered in a broker configuration. Issue the following commands on Primary database and Standby database to find out: Broker checks to see if Flashback Database is enabled on the primary and failover targets when FSFO is enabled. 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. The subdirectories that DGMGRL creates under this directory will also have the DGMGRL to manage multiple observers on multiple configurations. Switchover and Failover with DataGuard Broker on Oracle 19c - Data Alchemy During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. Flashing back a database occurs in two stages: For FSFO environments, set db_flashback_retention_target = 60 or higher to provide sufficient Flashback Database history for automatic standby reinstatement. This walkthrough uses Maximum Availability mode to achieve "zero data loss". the observer on ob2-host to become the master 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. RMAN will copy the spfile from the primary, so this init.ora file is only needed during the first phase of the duplication. Because fast-start failover was not disabled on the target standby database, the observer may still attempt a fast-start failover to the target standby database should conditions warrant a failover. 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. The walkthrough begins with a single database that will become the primary of a Data Guard configuration. The primary database was shut down without using the ABORT option. The broker reinstates bystander standby databases that were disabled during a failover as standby databases to the new primary database. There are two types of failover operations: Graceful or "no-data-loss" failover and Forced or "minimal-data-loss" failover. 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 In this case, no attempt is made to transmit any unsent redo from the far sync instance to the target physical standby prior to converting the physical standby into a primary database. These scripts must be in the same directory as the Application Continuity is supported for Oracle Data Guard switchovers to physical standby databases. Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. The following is an example of querying the V$FS_FAILOVER_STATS view: Disabling fast-start failover prevents the observer from initiating a failover to the target standby database. The service is then configured to be active in the PRIMARY role on the standby database SOUTH, so that it will be active on that database after a role transition. operation: Example 6-1 Fast-start Failover Configuration Its primary job is to perform a failover when conditions permit it to do so without violating the data durability constraints set by the DBA. ERROR: Unable to verify the graphical display setup. this script is run before the fast-start failover is initiated. To see the specific parameter, use the "show database StatusReport" command. That is, if the observer is connected to any instance in the Oracle RAC, all instances will show a value of YES. If you are not using Oracle Clusterware or Oracle Restart, then you must create static service names so that the observer can automatically restart a database as part of reinstatement. After a failover, a bystander will not automatically become the new failover target. If the FastStartFailoverPmyShutdown configuration property is set to TRUE, the primary database will shut down after FastStartFailoverThreshold seconds has elapsed if redo generation has been stalled and the primary database is unable to reestablish connectivity with either the observer or target standby database. Oracle Database 11g adds the ObserverConnectIdentifier database property to the Broker configuration, allowing you to specify a connect identifier for the observer to use for monitoring the primary and failover target. 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. Theoretically, this method can be used when a data guard failover occurred between the primary and standby database, but not a switchover. 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. Services that must be active in any given database role (primary, physical standby, logical standby, or snapshot standby) must be configured with the Server Control utility (SRVCTL) explicitly on each database where the service must be active. Oracle 19c-Performing Dataguard Switchover Using DGMGRL Utility commands. FAN events are always published through ONS. This section describes how to stay on top of your FSFO environments. To start an observer, you must be able to log in to DGMGRL with an account that has See Oracle Data Guard Concepts and Administration for information about tuning the log apply rate for a physical standby database. SQL>ALTER SYSTEM SWITCH LOGFILE; The foundation of FSFO is Data Guard - a primary and at least one standby. LinkedIn:https://www.linkedin.com/in/hari-prasath-aa65bb19/ If reinstatement of a database fails, its status changes to ORA-16795: the standby database needs to be re-created. Broker will set the primary to use asynchronous log transport by default. But it will also continue trying to reconnect to the primary database indefinitely. Guide to Oracle Data Guard Fast-Start Failover The guide makes few assumptions about your existing environment and includes examples for creating a physical standby database and Data Guard Broker configuration. See Performing Manual Role Changes When Fast-Start Failover Is Enabled for more information. FSFO can provide substantial gains in high availability and disaster recovery preparedness for all environments, from inexpensive Cloud-based systems to global distributed data centers. These facilities allow applications written to take advantage of them to receive asynchronous notification of database events, including role transitions. As a result the observer may still initiate fast-start failover to the target standby database, if conditions warrant a failover. How to switch roles in Oracle Data Guard - The Geek Diary drain_timeout amongst the active services. process. The FORCE option disables fast-start failover on the database to which you are connected even when errors occur.