data guard failover steps data guard failover steps

The commands that can be executed for a group of configurations (as declared in an observer configuration file) are as follows. *PATCH V3 0/6] ASoC: codecs: Add Awinic AW883XX audio amplifier driver [not found] <000701d8e7521f78bc05e6a340awinic.com> @ 2022-11-11 11:26 ` wangweidong.a 2022-11 . Oracle Data Guard can switch a standby database to the primary role in case a production database becomes unavailable due to . The playground: Database services can be configured to be active in specific database roles on Oracle RAC databases and on single-instance databases managed by Oracle Restart. There are prerequisites that must be met before the broker allows you to enable fast-start failover. It will also alert you to databases that have had Flashback Database disabled at some point after FSFO was enabled. Use the SHOW CONFIGURATION BystandersFollowRoleChange command to see the value of this property. Look for the desired data in the RAM. WAIT option, broker waits for the amount of alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. This database property is used to specify how the observer should connect to and monitor the primary and standby database. observers for a single Data Guard configuration. The default name of the observer runtime data file is When fast-start failover is disabled, no observer is called the master observer; all observers have the same functionality. It comes with a GUI and command line interface. For each broker configuration on which one or more The PeopleSoft application servers will react accordingly to FAN events Displays only on a logical standby database that has not yet completed loading a copy of the primary database's data dictionary. However, there may be exceptions to the recommendation to choose a physical standby database as the target standby database. In disaster situations where a failover is necessary, you may be more limited as to which standby database is the best one to pick up the failed primary database's activities. Create a pre-callout script, or a post-callout script, or both. Initiate the failover on the standby database STAN: SQL>connect /@STAN as sysdba SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; 2. Transitions the target standby database into the primary database role, as follows: Changes the role of the database from standby to primary. contains important information about the observer. If the standby database's redo applied point is within that many seconds of the primary database's redo generation point, a fast-start failover will be allowed. Albino DeSantis - Senior System Engineer - US Coast Guard - LinkedIn A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. have received all the redo data the primary has generated in order for automatic failover to Logical standby databases that are disabled during failover can be reinstated. file, observer runtime data file (fsfo.dat), fast-start failover callout The example below takes advantage of the 11g RMAN Active Database Duplication feature. Switchover/Failover operation in 2-node RAC and 2-node DATAGUARD To help you select an appropriate switchover or failover target, use the following DGMGRL commands which perform checks on the database to determine its readiness to complete a role change. an alias of the broker configuration name. Create a trigger based on the, Oracle Database PL/SQL Language Reference, Choosing a Target Standby Database for Switchover, Choosing a Target Standby Database for Failover, Scenario 9: Performing a Switchover Operation, Scenario 10: Performing a Manual Failover Operation, Database Service Configuration Requirements, Troubleshooting Problems During a Switchover Operation, How the Broker Performs a Complete Failover Operation, How the Broker Performs an Immediate Failover Operation, Setting the Protection Mode for Your Configuration, Scenario 7: Enabling Fast-Start Failover When a Far Sync Instance Is In Use, Description of "Figure 6-1 Relationship of Primary and Standby Databases and the Observer", Enabling Fast-Start Failover Task 7: Configure Actions Before and After Fast-start Failover (Optional), Directing a Fast-Start Failover From an Application, Fast-start Failover Callout Configuration Files, Oracle Data Guard Command-Line Interface Reference, Description of "Figure 6-2 The Observer in the Fast-Start Failover Environment", Oracle Enterprise Manager Command Line Interface. observer immediately begins monitoring the status and connections to A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. FastStartFailoverLagLimit configuration property. Set the, Configure the connect descriptor with a single network name that is registered with a global naming service such as DNS or LDAP. MASTEROBSERHOST TO command. Configure one or more active standby databases Minimize downtime for upgrades A simple example for *nix is provided below that will work with both releases. Manual failover gives you control over exactly when a failover occurs and to which target standby database. If no name is specified for the observer then a default observer name, the host name of machine where the START OBSERVER command is issued, is used. The column value for V$DATABASE.FS_FAILOVER_STATUS will be SYNCHRONIZED in a configuration operating in maximum availability mode, and it will be TARGET UNDER LAG LIMIT in a configuration operating in maximum performance mode when ready to fast-start failover. This results in the observer establishing a new connection to the primary database every 30 seconds. Running a StatusReport on the primary should verify that the error is due to a missing observer. If the target standby database is a snapshot standby database, all of its instances must be restarted to the mount mode before performing failover. file (fsfo.dat). Each group that you define must have at least one broker configuration. The reinstated database acts as the fast-start failover target for the new primary database, making a subsequent fast-start failover possible. Choose a value high enough to avoid false disconnects from intermittent network trouble. Default value is 10 miliseconds. Other members of the configuration will receive redo from the designated redo source based on the new primary. It has two parts in the following order: Configuration declaration this section is mandatory. When performing a failover in a configuration whose standbys are all of the same type, choose the standby database that has the smallest transport lag. Conditions shown in blue are enabled by default. In maximum performance mode, the ability to automatically failover is restored Oracle 19c-Performing Dataguard Switchover Using DGMGRL Utility Figure 6-1 shows the relationships between the primary database, target standby database, and observer during fast-start failover: Before Fast-Start Failover: Oracle Data Guard is operating in a steady state, with the primary database transmitting redo data to the target standby database and the observer monitoring the state of the entire configuration. On the Oracle Data Guard Overview page in Cloud Control, select the standby database that you want to change to the primary role and click Failover. Be aware that if you issue the following manual commands on either of those databases, then both the SALESRO and SALESRW services would be started on the databases regardless of what you may have earlier specified with the SRVCTL -role qualifier. The observer is perfectly satisfied if all of the redo it needs to meet your durability requirements has been received by the failover target. For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. 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. See Choosing a Target Standby Database for helpful advice. database's redo generation point by more than the value specified by the You cannot perform a manual failover to the target standby database for the same reason. 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. 4. redo generation on the primary database will be stalled. Simply use DISABLE FAST_START FAILOVER. 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. If groups are not defined, you can still operate on all configurations defined in the file as a whole. Displays the current fast-start failover mode. Oracle recommends configuring Flashback Database on every database so that if failover occurs to a physical standby database, you can more easily reinstate any disabled standby databases. DGMGRL> show configuration Configuration - CDB01_fraad1_CDB01_fraad3 Protection Mode: MaxAvailability Members: CDB01_fraad1 - Primary database CDB01_fraad3 - (*) Physical standby database Now let's test switchover in the other direction. Thus, the validity of the values of these properties is not verified until after the switchover. callout configuration file. must create a .suc and .err file in the There are configuration requirements that must be met in order to publish and properly handle FAN events generated as the result of a broker-managed failover. This action will result in loss of data and the possibility of two databases in the configuration simultaneously assuming the primary database role. For reliable startup, the initial connection should always be made to the primary. This section describes how to stay on top of your FSFO environments. If a database must be re-created from a copy of the new primary database, it will have the following status: Re-create the standby database from a copy of the primary database and then reenable it, as described in How to Re-create and Reenable a Disabled Database. If a single-instance primary database (either Oracle RAC or non-Oracle RAC), or if all instances of an Oracle RAC primary database are shut down with the ABORT option, the observer attempts a fast-start failover. environment variable must have exclusive permissions wherein it can be accessed only This list describes how the overall Oracle Data Guard protection mode is handled after a manual failover (complete or immediate). 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. When fast-start failover is enabled, the broker determines if a failover is necessary and initiates the failover to the current target standby database automatically, with no need for manual intervention. The ObserverOverride configuration property, when set to TRUE, allows an automatic failover to occur when the observer has lost connectivity to the primary, even if the standby has a healthy connection to the primary. File. What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? The existence of a .suc file, This is to ensure that the service definition gets propagated to the physical standby database via the redo stream and thus allows for the service to be started on the physical standby database. The only exception to this is failovers to snapshot standby databases. Data Guard. The Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. The drain_timeout is specified in the SRVCTL DG BrokerDG BrokerData Guard BrokerOracleDGRMAN Duplicate . Overall commit latency is increased by the round-trip network latency. By default, the broker always determines whether bystander standby databases will be viable standby databases for the new primary when performing a complete failover. 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. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. See Reenabling Disabled Databases After a Role Change. Step:6 The configuration must be operating in either maximum availability mode or maximum performance mode in order to be able to switch over to a logical standby database. In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. It is actually a low-footprint OCI client built into the DGMGRL CLI (Data Guard Broker Command Line Interface) and, like any other client, may be run on a different hardware platform than the database servers. Permissions Required by the DG_ADMIN Directory. 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. on ob3-host and ob4-host will not You can query the V$DATABASE view to verify that the observer is started and the configuration is ready for fast-start failover. This configuration property causes the former primary database to be automatically reinstated if a fast-start failover was initiated because the primary database was either isolated or had crashed. Example 6-2 Sample Observer Configuration File. gets enabled and then begins monitoring. Displays only on the target standby database when it is SYNCHRONIZED with or is TARGET UNDER LAG LIMIT of the primary database, has connectivity to the observer, but the primary database does not have a connection to the observer. For example: Scenario 6: Enabling Fast-Start Failover and Starting the Observer. 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. 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 Indexing is a mechanism by which the underlying data is mapped for faster retrieval. Step-B: Copy control file to temporary location on primary database. If the new primary database was a primary database in the past, and had block groups used by multiple configuration commands. This section describes how to configure and verify each prerequisite. Data Guard Failover to physical standby Tips - dba-oracle.com All other registered observers are considered to be backup observers. The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. 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. An observer process is integrated in the DGMGRL client-side component of the broker and typically runs on a different computer from the primary or standby databases and from the computer where you manage the broker configuration. Disabling Fast-Start Failover Using Cloud Control. 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. Displays if the standby database's redo applied point lags the primary database's redo generation point by more than the number of seconds specified by the FastStartFailoverLagLimit configuration property and the configuration is operating in maximum performance mode. Fast-start failover allows the broker to automatically fail over to a previously chosen standby database in the event of loss of the primary database. Complete Failovers in Configurations Using Cascaded Standbys. ObserverPingRetry properties before observer, whether it is currently connected to the primary and target standby databases, occur. See Prerequisites for more information. the observer was killed after the stall began, but before the failover timeout had elapsed). Click Disable in the Fast-Start Failover wizard. After the conversion, the broker will start Redo Apply to apply accumulated redo data, before failing the database over to the primary role. property. file also declares broker configurations and defines configuration commands. In order to accommodate all load conditions, Oracle recommends having at least one more SRL group than the number of ORL groups of the same size. If the configuration contains physical, snapshot, and logical standby databases, consider choosing a physical standby database as the target standby database. The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. Switchover to a logical standby database is disallowed when the configuration is operating in maximum protection mode. 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. It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). The new primary database starts transmitting redo data to the new standby database. 3. The FORCE option may be the preferred method for disabling A snapshot standby cannot be the target of a switchover or fast-start failover operation. Clusterware: The broker notifies Oracle Clusterware to stop active Note that a switchover operation may be started before the specified wait There is no need to multiplex SRLs in order to protect redo as with ORLs (the redo is already protected in the ORLs of the primary). The previous examples dealt with setting up only one service on a database. If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. Switches roles between the primary and standby databases. 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). A complete failover also attempts to avoid disabling any standby databases that were not the target of the failover, so that they may continue serving as standby databases to the new primary database. Starting Observers as Background Processes. observer and the others are backup observers. Setting it to 'FALSE' leaves the database open and stalled until it is terminated or signaled to proceed in the event a failover did not take place (e.g. 1 second. 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. 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. This nomination is noted in the observer log file and in the broker log file (drc*.log). The connect-identifier is a TNS alias defined in tnsnames.ora through which all instances of all databases in this Data Guard broker configuration can be reached. . If there are no registered observers when fast-start failover is enabled, then the first observer started is designated as the master observer, and all others started later are backup observers. This is typically done for planned maintenance of the primary system. With a value of TRUE for this property, the primary will shut down after being stalled for the number of seconds specified by the FastStartFailoverThreshold property. Another standby database that does not have connectivity with the primary database, fast-start failover is disabled for this database. Controlfile is permanently damaged because of a disk failure. STANDBY>connect /@STAN as sysdba This is normal. For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. 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. Just be sure to include a Flashback Database history check in the script to provide an option to abort if a failover would require a manual reinstate. It is not reversible. In this case, disable fast-start failover using the FORCE option on the target standby database. Oracle Data Guard Manual Failover - ORACLEAGENT BLOG By default, the observer uses the same connect identifiers used by Data Guard for redo transfer and information exchange between the primary and standby ( DGConnectIdentifier in Oracle Database 11g, InitialConnectIdentifier in Oracle Database 10g). Tasks that must be performed before and after a fast-start failover the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . There is little risk in enabling Flashback Database to determine its storage requirements - it can be disabled while the primary is open if necessary. If the failover fails for any reason, it could leave the target standby database inoperable, regardless of whether the target standby database is ready to failover. (Note: 11.1.0.7 adds the StaticConnectIdentifier Broker database property to allow you to specify a different service name.) Data Guard switchover with dgmgrl - dba-oracle.com 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. The database on which the procedure is called notifies the observer. If this 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. You want to conduct a manual failover to any standby database in the configuration (for example, because a failure occurred on the primary database at a time when the primary and target standby database were not ready to failover). The broker continuously monitors for all sessions that are connected The default value is ALL. The following is a sample observer configuration file: Since the broker configuration SALES consists of three databases, Boston, Chicago, and Dallas, with a CONNECT_ID of SALES_P, the SALES_P connect identifier must be defined such that it can reach any instance of any database within the configuration. Failing over the database won't do much good if applications and other database clients don't know where the primary went. Subsequent changes to the same block during the same snapshot are not recorded. How to reinstate the old Primary as a Standby after Failover in #Oracle FastStartFailoverAutoReinstate is set to FALSE, Another failover or switchover occurred after the fast-start failover completed but before the former primary database restarted, The master observer cannot connect to the former primary database, The former primary database cannot connect to the new primary database, The former primary database and the new primary database are not configured in the same fast-start failover environment, The former primary database was disabled because of a manual failover when fast-start failover was disabled. PRIM>STARTUP MOUNT; If these parameters are modified outside of Broker, it raises a warning. The syntax for the optional definition of a broker configuration group is: The group definition section is optional. The ObserverReconnect configuration property specifies how often the observer establishes a new connection to the primary database. The observer host is 'observer.demo.org'. Note: the FSFO observer version must match the database version. Bystander standby databases may be disabled by the broker during the failover, and they must be reinstated or re-created before they can serve as standby databases to the new primary database. The configuration and database status report the same error messages as are returned when there is only one registered observer. The minimum value of ObserverPingInterval is 100 If that metadata is pushed out, Oracle can no longer find a fuzzy snapshot so it will not be able to flash back. See Installing and Starting the Observer. If this operation is successful, a zero data loss failover may be possible even if the primary database is not in a zero data loss protection mode. If you don't already have a Flash Recovery Area (FRA), you will need to create one for Flashback Database. If there is only one observer, then it is considered to be the master observer. They must be re-created from a copy of the new primary database. Enabling fast-start failover and starting an observer process involves the following tasks.