In an Oracle Data Guard configuration, the SRVCTL -startoption for a standby database is always set to OPEN after a switchover. To verify this change, again query the Database_role column of V$DATABASE. If fast-start failover is The default name for Configure the TNSNAMES.ORA file on the observer system so that the observer is able to connect to the primary database and to the pre-selected target standby database. 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. In the restore stage, Flashback Database restores the database to a point prior to the standby_became_primary_scn using the before-image blocks in the Flashback Database logs. guaranteed to lose no data. You can perform a manual failover even if fast-start failover is enabled. A complete failover can occur without any data loss, depending on the destination attributes of redo transport services, but an immediate failover usually results in some data loss. To start an observer, you must be able to log in to DGMGRL with an account that has All database connections associated with the observer, including the initial connection, must use dedicated server connections. If no value is specified for the 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. See the Oracle Reference and Data Guard Administrator guides for your release for details. through these services to exit or for the specified wait time The observe-only mode for fast-start failover enables you to test how fast-start failover will work in your environment. The time interval specified by the FastStartFailoverThreshold property is ignored if the master observer detects that a user-configurable condition has occurred or if a fast-start failover has been requested by the DBMS_DG.INITIATE_FS_FAILOVER function. required permissions, fast-start failover callouts will fail. When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. This guide uses the naming convention of appending an underscore followed by a letter to the db_name to create the db_unique_name. However, there may be situations in which you must disable fast-start failover when set the ObserverPingInterval and See Oracle Data Guard Concepts and Administration for more information on using the ALTER SYSTEM FLUSH REDO statement. The following sections provide information about managing observers: How the Observer Maintains Fast-Start Failover Configuration Information, Patching an Environment When the Observer Is Running and Fast-start Failover Is Enabled. 4. Initiate the failover on the standby database STAN: These tasks assume that you are connected as SYS or SYSDG and that a primary and standby database are already set up in a broker configuration. Enable Fast-Start Failover Using Cloud Control. To see Manual Switch Over Manual SwitchOver in Oracle To see Manual Fail Over Manual Failover in Data Guard With Oracle Data Guard [] Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. fast-start failover operation, the observer checks if a fast-start failover This is true regardless of the settings for the FastStartFailoverPmyShutdown and FastStartFailoverAutoReinstate configuration properties. Whether or not you need the FORCE option depends mostly on if the primary and target standby database have network connectivity: If the primary and target standby database have network connectivity, and the database to which you are connected has network connectivity with the primary database, the FORCE option has no effect. Enabling fast-start failover in a configuration operating in maximum performance mode provides better overall performance on the primary database because redo data is sent asynchronously to the target standby database. This specifies how often the observer establishes a new connection to the primary database. Immediate Failovers in Configurations Using Far Sync Instances. An observer can be moved from one computer to another through a process of stopping it on one system and and re-starting it on another. You can optionally indicate the database health conditions that should cause fast-start failover to occur. Before a If automatic reinstatement fails, the broker will log errors and the former primary database will remain in the mounted state. *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 . FastStart Failover Ensues: Disaster strikes the primary database and its network connections to both the observer and the target standby database are lost. The broker allows a complete failover to proceed as long as there are no errors present on the standby database that you selected to participate in the failover. To enable fast-start failover in Cloud Control, use the Fast-Start Failover wizard. Oracle Corporation recommends that you specify this type of failover. 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. REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. To restore your original disaster-recovery solution after switchover to a logical standby database or after failover to any standby database, you may need to perform additional steps. configuration file Ensure SPFILE is used SQL> sho parameter spfile 2. As shown in the table, fast-start failover can be enabled in maximum availability For this build, we will use a single physical standby database. SWITCHOVER command, and the databases are managed by Oracle observers are registered, a directory named What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. instructions for the DGMGRL command-line interface. Reinstate or re-create standby databases in the configuration that were disabled by the broker. times that the observer retries a failed ping before it initiates a It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). See Oracle Enterprise Manager Command Line Interface. FAN events are always published through ONS. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. For a system to process an instruction involving data access, these are the certain steps involved: Fetch the block of data from the hard disk (secondary/permanent storage) to the primary memory (e.g. callout configuration scripts fsfo_precallout and US Coast Guard Auxiliary. You cannot perform a manual failover to the target standby database for the same reason. If the observer finds that the database is no longer the primary, it will attempt to reinstate it as the failover target standby. /home1/dataguard/config_NorthSales/callout/fsfocallout.ora. under the $DG_ADMIN directory. By default, the observer uses the same connect identifiers used by Data Guard for redo transfer and information exchange between the primary and standby ( DGConnectIdentifier in Oracle Database 11g, InitialConnectIdentifier in Oracle Database 10g). In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. If both the observer and designated standby database lose connectivity with the primary database for longer than the number of seconds specified by the FastStartFailoverThreshold configuration property, the observer will initiate a fast-start failover to the standby database. (Oracle Call Interface) client that connects to the primary and target standby databases property. Stores files related to the observer and callout configuration. In order to fully automate switchover, Broker needs SYSDBA credentials in order to restart one or both databases. To determine if the configuration is ready for fast-start failover to occur, issue the DGMGRL SHOW DATABASE command, or query the V$DATABASE view on either the primary or target standby databases. Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. Another consequence of immediate failover is that all other databases in the configuration are disabled and must be reinstated or re-created before they can serve as standby databases for the new primary database. Now we will see a step-by-step approach to perform a switchover between the primary and the logical standby database: . For Active Oracle Data Guard, it will fail to open up a connection unless its in read-only mode. Log in as a test user and make some changes that won't impact other parts of the system. directory. Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). 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. VALIDATE 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. This feature increases the availability of your database in the event of a disaster by reducing the need for you to perform a failover operation manually. Broker will set the primary to use asynchronous log transport by default. For the RMAN duplicate active database method, the init.ora file (initdb1.ora in the example) requires only one parameter: db_name (it doesn't even have to be the real name of the database - any name will do). Configure Data Guard Broker to manage and monitor the Data Guard configuration. For reliable startup, the initial connection should always be made to the primary. To use a far sync instance with fast-start failover, the far sync instance transport mode must be set to either SYNC or FASTSYNC and the target standby database transport mode must be set to ASYNC. 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. The target standby database has contact with the primary database. 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 starting an observer as a background process: The START OBSERVER IN BACKGROUND command uses Oracle wallet to obtain credentials to log into the database server and register observers. A high lag limit may lead to more data loss but may lessen the performance impact of the primary database. Attempt to open the primary database, or the following error may be returned: This error may return if the fast-start failover validity check fails or does not complete in under two minutes. The Appendix provides information oncreating a simple wrapper script to start the observer as a background process. FB Group:https://www.facebook.com/groups/894402327369506/ After an immediate failover completes, all the standby databases in the configuration, regardless of their type, are disabled. Figure 6-1 Relationship of Primary and Standby Databases and the Observer. (Note: 11.1.0.7 adds the StaticConnectIdentifier Broker database property to allow you to specify a different service name.) Create a script to automate FSFO failover initiation and use it as your standard method for standby flips. Step-by-step instructions for manual reinstatement are described in Reenabling Disabled Databases After a Role Change. The following paragraphs describe the supported availability modes. become the master observer. Verify Before Switch-over: For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. It uses the connect identifier specified in the observer configuration file to locate the credentials for a broker configuration from the Oracle wallet. 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. An application should use caution when calling the DBMS_DG.INITIATE_FS_FAILOVER function because the observer will initiate failover, if at all possible. Application Continuity is an Oracle Database feature that enables rapid and nondisruptive replays of requests against the database after a recoverable error that made the database session unavailable. See FastStartFailoverTarget for more information about this property. If the failover target database is an Oracle RAC physical or snapshot standby database, the broker directs Oracle Clusterware to restart all instances that may have been shut down prior to the failover. If both of those observers are unavailable, the observers 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. The following list indicates the extent to which fast-start failover is disabled in the broker configuration when the DISABLE FAST_START FAILOVER FORCE command is issued on the primary database, target standby database, and a standby database that is not the fast-start failover target. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. If the Broker configuration is changed to make a bystander the new failover target (probably a good idea if the failed database will be down for a while), the observer will not automatically reinstate the former primary because it is no longer part of the FSFO configuration. For more information, see SET MASTEROBSERVER TO. occurred to the target standby database prior to disabling fast-start But before enabling Flashback Database, you must enable Flash Recovery Area (FRA). Errors occurring for any other configuration members will not impede the switchover. After Fast-Start Failover: The fast-start failover has completed and the target standby database is running in the primary database role. 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. Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. Use the wrapper script to start the observer process when the observer host boots or to restart it if it dies. The reinstated database acts as the fast-start failover target for the new primary database, making a subsequent fast-start failover possible. ConfigurationSimpleName. change tracking enabled, broker enables block change tracking on the new In a Managed Instance with multiple databases in Azure we can have high availability. This directory is created when you run the They cannot be reinstated. You can customize fast-start failover setup for a specific application by using the DBMS_DG PL/SQL package. (It is permissible to change the RedoRoutes property on all standby databases including target standby databases. 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. mode when the fast-start failover target is a logical or physical standby database that You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. Fast-start failover enables the Data Guard broker to rapidly and automatically failover to a previously chosen standby database without requiring manual intervention. No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. Performing a Manual Failover Task 1: Determine Which of the Available Standby Databases is the Best Target for the Failover, Performing a Manual Failover Task 2: Start the Failover, Performing a Manual Failover Task 3: Reset the Protection Mode, Performing a Manual Failover Task 4: Re-establish a Disaster-Recovery Configuration. 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. 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. In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). The database cannot provide fast-start failover status information. Except for testing purposes, it is not recommended that you start more than one observer on the same host for a Data Guard broker configuration. Setting this property to 'TRUE' (the default) causes the primary to self-terminate. 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 you initiated a complete failover and it fails, you might need to use immediate failover. Expected output is shown in blue text. Therefore, the detection time can be reduced to nearly See Choosing a Target Standby Database for helpful advice. Oracle Data Guard can switch a standby database to the primary role in case a production database becomes unavailable due to . maximum availability and maximum performance modes, to avoid a lose no more than the amount of data (in seconds) specified by the Examine the Broker configuration by logging into dgmgrl on the new primary. A far sync instance or Zero Data Loss Recovery Appliance is not a database and therefore cannot be the target of a role transition. 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. Change Standby to Primary Database. There is little risk in enabling Flashback Database to determine its storage requirements - it can be disabled while the primary is open if necessary. What is true about Data Guard setup with fast-start 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). An alternative is to enable flashback database on the primary (and the standby if desired) so in the event of a failover, the primary can be flashed back to the time before the failover and quickly converted to a standby database. the ObserverPingRetry and ObserverPingInterval properties to achieve Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. Stops Redo Apply or SQL Apply on the standby database immediately, without waiting until all available redo data has been applied. select name,open_mode,database_role from v$database; Note: STANDBY>ALTER DATABASE OPEN; In this example, the original primary data is called PRIM and the original standby database is called STAN. Make sure the last redo data transmitted from the Primary database was applied on the standby database. You must manually re-create the database as a standby database and then reenable it. Any apply delay must be removed before beginning a switchover. FastStartFailoverLagLimit configuration property. Fast-start failover is enabled, but this standby database is not the target of the fast-start failover. The broker allows the switchover to proceed as long as there are no errors for the primary database and the standby database that you selected to participate in the switchover operation. The failover time is dependent upon whether the target standby database (physical or logical standby database) has applied all of the redo data it has received from the primary database. learning with R and Python are also covered in this step-by-step tutorial. Step 4: Enable Fast-Start Failover Now we are ready to enable FSFO: DGMGRL> enable fast_start failover; Enabled in Zero Data Loss Mode. Ideally the primary, standby, and observer will be in geographically separate areas. The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. When the standby becomes available again, the primary and standby re-synchronize and resume synchronous redo transfer. For example: Ordinarily the observer connects once to the primary and does not attempt to reconnect unless the connection has failed. gets enabled and then begins monitoring. this directory are used to store the files related to the These conditions are described in the following table: Dictionary corruption of a critical database. Role Transitions: Switchover and Failover 1 -7 Oracle Data Guard Broker Framework 1 -9 C hoosing an Interface for Administering a Data Guard Configuration 1 -10 Oracle Data Guard: Architecture (Overview) 1 -11 Primary Database Processes 1 -12 . This post will demonstrate the procedure to test Oracle Data Guard Fast-Start Failover by shutting down the server where the primary database is running from. 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. This is called failover. 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. Verify the target standby database is ready for failover. When you run commands that need access to the observer You have done a failover to your Standby database so it becomes the new Primary. post-callout script, and pre-callout success file for the broker SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. This article - the seventh in this ongoing . 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. Verify there are no active users connected to the databases. Chapter 9 of the Data Guard Broker documentation (10g and 11g) contains a description of each property. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. You must determine which available standby databases should be targets for failover. This function can be called from a connection to either the primary or any standby in the configuration. During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. This is the recommended method for disabling fast-start failover. Cloud Control will start the observer. FastStartFailoverLagLimit property. Suppose you have a primary database, BOSTON, and a standby database, CHICAGO. Switchover and Manual Failover for more information about switchovers and manual failovers, respectively. This list contains some recommendations to obtain better performance when using fast-start failover. A good method to determine Flashback Database storage requirements is to enable Flashback Database and observe the amount of storage it uses during several peak loads. 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. If the database is not enabled, you will not be able to perform a failover to this database. It could optionally also be removed from the primary database if there is no intention to ever run this service on the current primary database. This document only talks about switchover involving physical standby database. ensure that it has the required permissions. However, if you want the observer to reconnect to the primary database periodically as a means of testing the health of the network connection to the primary, then use the ObserverReconnect configuration property. If the primary database does not have connectivity with the target standby database, fast-start failover remains enabled on the target standby database and the observer may still attempt a fast-start failover if conditions warrant a failover. Use the 'show fast_start failover' command to see which user configurable FSFO failover conditions are in effect. Add the primary database and each standby database to the address list. Starting the Observer Using Cloud Control. The broker controls the rest of the switchover. This action may result in two databases in the configuration simultaneously assuming the primary database role. The failover was to a logical standby database. SQL>SHUTDOWN IMMEDIATE; Before stopping an observer, note the following: The observer does not stop immediately when you issue the STOP OBSERVER command. ObserverPingRetry properties before CONNECT command. *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 . For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. Observer sites monitor the fast-start failover environment. You need to consider all of the options at the time you are building your Oracle Data Guard configuration, including factors such as the characteristics of physical standbys versus logical standbys versus snapshot standbys, the network latency to your standby database sites, the computing capabilities at a future primary database site, and so on. Note that the new primary database does not need to be restarted. Note that if failover was performed on a snapshot standby database, the old primary must be either reinstated or re-created as a physical standby database. The observer is the third party in an otherwise typical primary/standby Data Guard configuration. The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. If you re-create the old primary database, it must be created as the standby type of the old standby database. Broker changes database parameters during startup and role transitions via ALTER SYSTEM commands. The following example displays the contents of the fast-start failover A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. create the directory specified by the DG_ADMIN environment variable and

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