The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. Reinstate the former primary database as a new standby database. Bystander standby databases can be shut down at any time in any order without impacting fast-start failover. 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. this directory are used to store the files related to the on ob3-host and ob4-host will not The commands that can be executed for a group of configurations (as declared in an observer configuration file) are as follows. These clients can be configured for Fast Connection Failover (FCF) to automatically connect to a new primary database after a failover. You cannot perform a switchover to a snapshot standby database unless you first convert it back to a physical standby database. (If there are other conditions, unique to an application, that would warrant a fast-start failover then the application can be set up to call the DBMS_DG.INITIATE_FS_FAILOVER function and start a fast-start failover immediately should any of those conditions occur. You can also reinstate bystander standby databases that were disabled during a failover operation. For each observer, the V$FS_FAILOVER_OBSERVERS view provides the Credentials Required for Access to Broker Configurations. At a minimum, you must set db_unique_name. This article - the seventh in this ongoing . milliseconds and that of ObserverRetryCount is 10. To stop an observer currently designated as the master observer, first issue the SET MASTEROBSERVER command to designate a different observer as master observer. SQL>STARTUP; For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. DG BrokerDG BrokerData Guard BrokerOracleDGRMAN Duplicate . The broker initiates a failover after the number of seconds specified by this FastStartFailoverLagLimit property. 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. Instead, Oracle Clusterware opens PDBs on particular instances based on If the database is managed by Oracle Clusterware, broker does not open any of the Broker is a Data Guard management utility that maintains state information about a primary and its standby databases. For this build, we will use a single physical standby database. operation can be automated using callout scripts. failure on the primary database. Step:5Bounce your database and verify database name its open mode and its role. 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 the names of the scripts created in the previous step. this script is run before the fast-start failover is initiated. The failover was to a logical standby database. Install the DGMGRL command-line interface on the observer computer as described in Oracle Data Guard Installation. This is the recommended method for disabling fast-start failover. In this case, disable fast-start failover using the FORCE option on the target standby database. Nothing will ruin your day faster than finding out that the standby the observer just failed over to is 12 hours behind in applying redo. The command SHOW FAST_START FAILOVER shows a list of registered observers and indicates which one is the master. SQL>ALTER SYSTEM SWITCH LOGFILE; If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. The most common problems are mismatched Data Guard protection modes and LogXptMode properties and forgetting to enable Flashback Database on the primary or standby. stored in the specified path using the default file names. 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. A simple example for *nix is provided below that will work with both releases. The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. Otherwise, they must be re-created from a copy of the new primary database. To prevent automatic reinstatement of the former primary database in these cases, set this configuration property to FALSE. The broker will not allow a switchover to a standby that has an apply delay configured (DelayMins property is set to a non-zero value). fsfocallout.ora. This not only saves time and minimizes problems by automating an otherwise manual process, it exercises your failover and DR procedures with every flip so that you know the FSFO configuration is sound and, in a real emergency, everyone knows what to do. Configure Data Guard Broker to manage and monitor the Data Guard configuration. The default group is all the configurations defined in the observer configuration file. Disabling fast-start failover does not stop the observer. configuration file, such as START OBSERVING, See Performing Manual Role Changes When Fast-Start Failover Is Enabled for more information. In an Oracle Data Guard configuration, the SRVCTL -startoption and -role are updated after switchover to reflect the current open mode and database role on the new primary and standby databases. We can always fail over to it or have it happen automatically if for some reason the primary Managed Instance has [] The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. An immediate failover should only be performed when a complete failover is unsuccessful or in the error cases just noted. failover configuration file, this script is run. The Column Value in the following table is consistent across instances in an Oracle Real Applications Clusters (Oracle RAC) environment. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by Sets up redo transport from the new primary to the other members of the configuration, Starts Redo Apply services on the new standby, Ensures the other standbys in the broker configuration are viable to the new primary, Integrates with Oracle Clusterware and Oracle Global Data Services (GDS) to ensure that the proper services are started after a role change. The only exception to this is failovers to snapshot standby databases. database. If this occurs, run 'stop observer' and try again. If you want to use one Oracle home to start multiple observers, with each observer monitoring a different fast-start failover configuration, use the FILE qualifier to specify a unique observer configuration file location for each configuration to be monitored. You can switch over or manual failover to a bystander database. Starting Multiple Observers On a Single Host. 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. The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. Now let's test switchover in the other direction. However, the event notifying a failover is only published for database services that have been configured to be active while the database is in the primary role on the new primary database. 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. command for more information about starting the Note that primary and standby databases must be licensed for Oracle RAC or Oracle Active Data Guard in order to use Application Continuity. If there is only one registered observer, then it works in the same manner that a single observer worked prior to the advent of multiple observers in Oracle Database 12c Release 2 (12.2.0.1). For reliable startup, the initial connection should always be made to the primary. The FORCE option may be the preferred method for disabling Verify the target standby database is ready for failover. This nomination is noted in the observer log file and in the broker log file (drc*.log). The logs also contain other details about the actions that will be performed in case of a failover. Starts redo transport services to begin transmitting redo data to all bystander standby databases that were not disabled. If any errors occur during either conversion, the broker stops the switchover. 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. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . 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). It must appear as the first part of an observer configuration file. Steps to Create a Physical Standby Databa se 3 -3 Preparing the Primary Database 3 -4 FORCE LOGGING . *PATCH v5 0/6] Add Toshiba Visconti Video Input Interface driver @ 2023-01-11 2:24 Yuji Ishikawa 2023-01-11 2:24 ` [PATCH v5 1/6] dt-bindings: media: platform: visconti: Add Toshiba Visconti Video Input Interface bindings Yuji Ishikawa ` (5 more replies) 0 siblings, 6 replies; 42+ messages in thread From: Yuji Ishikawa @ 2023-01-11 . However, fast-start failover cannot occur when the target standby database is in an unobserved state. If automatic reinstatement fails, the broker will log errors and the former primary database will remain in the mounted state. Client-side broker This section describes how to stay on top of your FSFO environments. When the observer loses its connection to the primary database for a period of time greater than that specified by the FastStartFailoverThreshold property, it attempts a failover to the standby database. This means that in order for a flashback database operation to succeed, observer and the standby both lose contact with the primary. If the new primary database was a primary database in the past, and had block After a switchover completes, the broker preserves the overall Oracle Data Guard protection mode as part of the switchover process by keeping the protection mode at the same protection level (maximum protection, maximum availability, or maximum performance) it was at before the switchover. Once an observer is started, no further user interaction is required. 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. Data Guard broker publishes this service on each instance as it comes up and broker management of the instance is initialized: To patch an environment where the Observer is running and fast-start failover is enabled, follow these steps prior to applying the patch. 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. Fast-start failover can incur data-loss within the time specified by FastStartFailoverlagLimit. It's good practice to use separate listeners for application connections and Data Guard connections. After a failover, the broker publishes Fast Application Notification (FAN) events. After the restart, Redo Apply begins applying redo data from the new primary Only two databases, the primary and the failover target, can be in the FSFO configuration at any given time. By default, both files are stored in $ORACLE_HOME/dbs. Fast-Start Failover in Oracle 11g Data Guard. configuration named ConfigurationSimpleName. (Yes, bystanders need Flashback Database too). become the master observer. property. The original primary database will be restarted as a part of the switchover operation. Open another prompt and connect to SQLPLUS: Starting Observers as Background Processes. alter database recover managed standby database finish; alter database activate standby database; Managed recovery process has been stopped between primary and standby database and standby becomes primary database. Stores the observer runtime data file and observer configuration file in Issue the following command while connected to any database in the broker configuration, except the database that is to be reinstated: The newly reinstated standby database will begin serving as a standby database to the new primary database. You can, however, perform a manual failover to a snapshot standby. 1,000,000 block changes on a small set of blocks generates less Flashback Database history than 1,000,000 changes on a larger set of blocks. primary database must have network connectivity. If Flashback Database was enabled on the primary database.If not, the whole setup process must be followed, but this time using the original primary server as the standby. Monitor the environment to ensure the primary database is available. They must be re-created before they can serve as standby to the new primary database. Broker will verify that the configuration meets all prerequisites before enabling FSFO and will report any problems it finds. By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. FSFO enabled configurations having multiple standbys cannot switchover to a standby that is not the failover target. 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. Database hosts are referred to as "a" and "b" hosts and the databases themselves are referred to as the "a" and "b" databases. Figure 6-2 The Observer in the Fast-Start Failover Environment. See Installing and Starting the Observer. The following conditions apply when multiple observers are registered for one configuration: When fast-start failover is enabled, one of the observers is the master observer. Make sure that your OS environment on the standby is setup. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). Therefore, the primary database can continue processing transactions, even if the target standby database fails. The new standby database is a viable target of a failover when it begins receiving redo data received from the new primary database. Issue the following commands on Primary database and Standby database to find out: In the following example, ObserverReconnect is set to 30 seconds. created under this directory by DGMGRL will also have the same permissions. FSFO is a feature of Broker which records information about the failover target, how long to wait after a failure before triggering a failover, and other FSFO specific properties. The example uses 10 seconds. 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. SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. fast-start failover, you can issue the DGMGRL SHOW FAST_START FAILOVER, To start an observer, you must be able to log in to DGMGRL with an account that has Displays on the primary database after loss of connectivity to the target standby database and the change to the UNSYNCHRONIZED state (maximum availability mode) or to the TARGET OVER LAG LIMIT state (maximum performance mode) cannot be confirmed by either the target standby database or the observer. Broker keeps its configuration details in flat file. Reinstating the Former Primary Database in the Broker Configuration for more information about reinstatement. When you are experiencing network disconnections and you issue the DISABLE FAST_START FAILOVER FORCE command on the primary database or a standby database that does not have connectivity with the primary database, fast-start failover may not be disabled for all databases in the broker 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. Verify Before Switch-over: 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. See Reenabling Disabled Databases After a Role Change. The command fails if the file does not exist. Writing the wrapper itself and the means to determine when to execute it are up to you. Since a fast-start failover (automatic failover) could become a false failover when the observer or the standby database cannot connect to the primary database within a specific time, which may cost the database to lose some transactions followed by reinstating or recreating the standby database (the former primary database). 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. The following table summarizes which standby types are supported in which protection modes when fast-start failover is enabled. If one of these errors has occurred, follow the guidelines in "Resolving ORA-752 or ORA-600 [3020] During Standby Recovery" in My Oracle Support Note 1265884.1 before proceeding. To see Manual Switch Over Manual SwitchOver in Oracle To see Manual Fail Over Manual Failover in Data Guard With Oracle Data Guard [] Refer to the appropriate Oracle RAC or Oracle Restart documentation for further information. Table 6-3 FS_FAILOVER_OBSERVER_PRESENT Column of the V$DATABASE View, The master observer is currently connected to the local database, The master observer is not connected to the local 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/. Keep this trigger as simple and reliable as possible, limiting it to only what is absolutely necessary at the moment of role transition, since any failures at this point may affect availability. DGMGRL to manage multiple observers on multiple configurations. The string "NONAME" cannot be used as an observer name. files are stored in subdirectories of the DG_ADMIN directory. lose no more than the amount of data (in seconds) specified by the multiple, inexpensive servers is the basis for the failover and other fault-tolerance features that RAC provides. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . Fast-Start Failover allows Data Guard to automatically failover to a previously chosen standby database without requiring manual intervention to invoke the failover. To run an observer as a background process, use the DGMGRL command START OBSERVER IN BACKGROUND. If there is only one standby database in the configuration, you can skip this step and continue with Task 3. For more details about managing redo transport services using database properties, see Managing Redo Transport Services. Valid values are >= 10. After the broker receives the STOP OBSERVER request, the request is passed to the observer the next time the observer contacts the broker, and the observer then stops itself. Alternatively, you can query the V$DATABASE view on the target standby database. As mentioned above, Maximum Availability mode is mandatory for Oracle Database 10g and optional for Oracle Database 11g. 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. 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). Automatic failover is optional and can be enabled or disabled on your Autonomous Container Databases with Autonomous Data Guard. FAN events are published using Oracle Notification Services (ONS) for all Oracle integrated database clients in Oracle Database 12c and later. 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. Metadata for the fuzzy snapshot is stored in the flashback log itself. If you are performing an immediate failover, then the database role is changed to primary without applying any accumulated redo data. from another DGMGRL session. 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. This section will help you get started with creating a wrapper script to automatically start and restart the FSFO observer. observer name, host, whether it is the master observer, when it became the master In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. Switches roles between the primary and standby databases. The new primary database is opened in read/write mode and redo transport services are started. These commands can be issued from the DGMGRL command line, but it is not necessary to log on prior to using them. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. You can query the V$FS_FAILOVER_STATS view on the primary database to display statistics about fast-start failovers that have occurred on the system. We suggest you try the following to help find what youre looking for: This document will guide you through configuringOracle Data GuardFast-Start Failover (FSFO) using a physical standby database. This configuration property establishes an acceptable limit, in seconds, that the standby is allowed to fall behind the primary in terms of redo applied, beyond which a fast-start failover will not be allowed. 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. This support note is available at http://support.oracle.com. Unlike the primary / standby interconnect, where bandwidth and latency are determining performance factors, the observer requires very little network bandwidth and is not overly latency sensitive, allowing the it to be placed practically anywhere a reliable connection is available. Although redo transfer is synchronous, Maximum Availability mode allows the primary to remain available if the standby database becomes unavailable for any reason (e.g. Note that the broker does not use the properties to set up redo transport services and Redo Apply services until you actually switch over the primary database to the standby role.
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data guard failover steps