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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. You can specify particular conditions for which a fast-start failover should occur using either Cloud Control or the DGMGRL ENABLE FAST_START FAILOVER CONDITION and DISABLE FAST_START FAILOVER CONDITION commands. If multiple observers have been started for the configuration, then be sure to specify the name of the observer whose environment is to be patched (STOP OBSERVER observer-name). What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? FB Group:https://www.facebook.com/groups/894402327369506/ Prepare the primary database in advance for its possible future role as a standby database in the context of the overall protection mode (see Managing Data Protection Modes). Oracle Database Reference for more information about the V$FS_FAILOVER_OBSERVERS view. To specify which observer can be a master observer when a database is in command does not have a network connection to the primary database. A database in the primary role will not open until it has verified with the observer that it is still the primary. 99 Software Similar To Oracle Data Guard Backup & Sync The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. As described in theFlashback Database section, Flashback Database takes place in two stages: a restore stage and a media recovery stage. 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 . Ideally the primary, standby, and observer will be in geographically separate areas. 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. Note the primary and target standby must have connectivity for this command to complete successfully. The broker reinstates the database as a standby database of the same type as the former standby database of the new primary database. Now your old standby database is become primary database, it is highly recommended to consider immediate full backup of primary database. When you configure data guard using OCI console, the default mode is set to maxprotection. 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). 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). 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. Credentials Required for Access to Broker Configurations. To stop a specific observer when there are multiple registered observers running, issue the following command: You can log into DGMGRL from any machine to stop an observer. (Snapshot standbys are not included in the table because they are not supported as fast-start failover targets.). The Column Value in the following table is consistent across instances in an Oracle Real Applications Clusters (Oracle RAC) environment. (Note that the target standby cannot be a far-sync instance. 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. The old Primary must have been running in flashback mode before the failover. switch does not happen until the next time the primary contacts the target standby, A switch-over allows the primary database to switch roles with its standby database. Performing failover : Step 1: Check Standby Database role. Displays if the standby database's redo applied point does not lag 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. *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 . Monitoring flashback database history and reacting when it drops below 30 minutes will save you time and improve availability. These facilities allow applications written to take advantage of them to receive asynchronous notification of database events, including role transitions. In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). The pre-callout script What is true about Data Guard setup with fast-start failover? The primary database can be opened even if there is no acknowledgement from the observer or target standby. If the value is non-zero, failover is possible any time the standby database's apply A trigger on the DB_ROLE_CHANGE system event can be used to update the naming service and, with the proper client cache TTL settings, clients can connect to the new primary very quickly. property. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. 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. This action will result in loss of data and the possibility of two databases in the configuration simultaneously assuming the primary database role. If the target is a snapshot standby database, the broker first converts the database to a physical standby database. The You can switch over or manual failover to a bystander database. ConfigurationSimpleName. 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. 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. (Yes, bystanders need Flashback Database too). 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 document describes how to setup clients to connect to Data Guard databases (primary and standby) and configure automatic client failover such that in case there is role change due to switchover or . What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? Then, 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. It is then started and stopped on the primary database. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL. You will have to reinstate or re-create (see Reenabling Disabled Databases After a Role Change) the standby databases after failover has completed. The original primary database will be restarted as a part of the switchover operation. If you performed a failover or switchover that requires you to re-create the failed primary database or standby databases that were disabled during the role transition, then follow the procedures in the Oracle Data Guard Concepts and Administration chapter, "Creating a Physical Standby Database" and also the Oracle Data Guard Concepts and Administration chapter, "Creating a Logical Standby Database.". For more information, see SET MASTEROBSERVER TO. 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. See Disabling Fast-Start Failover. observer. See Manual Failover for complete information about manual failovers. name of the observer log file is 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. Example 6-2 Sample Observer Configuration File. That is, if the observer is connected to any instance in the Oracle RAC, all instances will show a value of YES. The default value is 30 seconds and the lowest possible value is 5 seconds. The syntax for the optional definition of a broker configuration group is: The group definition section is optional. Broker keeps its configuration details in flat file. performance protection mode with fast-start failover. 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. Being FSFO ready means that all conditions are met for a successful failover, including having a running observer and sufficient redo transmitted to the failover target to meet durability requirements. We'll start it interactively for now to verify that everything's working. In the rare event that a switchover operation fails and you are left with no primary database, retry the switchover command. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. instructions for the DGMGRL command-line interface. 12c Dataguard, In Cancel MRP process. For example: In the following example, assume the network between the primary database and the observer has failed. Syntax for Mandatory Configuration Declaration. Some properties have changed between those releases. Make some new changes and verify that they are preserved after failover. More specifically, we can have an asynchronous second read-only Managed instance in the same or in a different region. Databases that have been disabled after a role transition are not removed from the broker configuration, but they are no longer managed by the broker. Because the broker performs the failover after converting the snapshot standby database to a physical standby database, 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. (It is permissible to change the RedoRoutes property on all standby databases including target standby databases. Then set the configuration protection mode to maximum availability. Once you set these properties, their values persist through role changes during switchover and failover. Applications can initiate FSFO failover directly using the DBMS_DG.INITIATE_FS_FAILOVER procedure with an optional message text that will be displayed in the observer log and the primary's alert log. Waits for the target standby database to finish applying any unapplied redo data before stopping Redo Apply (if the target is a physical standby database) or SQL Apply (if the target is a logical standby database). That process is shown here. The VALIDATE FAST_START FAILOVER command parses the callout from another DGMGRL session. Oracle FAN with Oracle Data Guard but without using Oracle Grid/ RAC Broker will set the primary to use asynchronous log transport by default. data (in seconds) specified by the variable must have read, write, and execute permissions for the directory owner In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. 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. Both Cloud Control and the DGMGRL CLI will do this automatically as part of failover. It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). It is instructive to watch the alert logs on both databases as well as the observer log after aborting the primary to gain insight into what happens during FSFO failover. The default name of the callout configuration file is The broker reinstates a failed primary database as a standby database of the same type (physical or logical standby database) as the old standby database. On Linux/Unix, the directory specified by the DG_ADMIN environment 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. If there is only one standby database in the configuration, you can skip this step and continue with Task 3. How to Test Data Guard Fast-Start Failover by Shutting Down Primary The broker interacts with Oracle Clusterware or Oracle Restart to ensure that the appropriate database services are active and that the appropriate FAN events are published after a role change. fast-start failover. services. The minimum detection time is 6 seconds, which is the default Chapter 9 of the Data Guard Broker documentation (10g and 11g) contains a description of each property. add service command. It automatically sets Data Guard related database initialization parameters on instance start and role transitions, starts apply services for standbys, and automates many of the administrative tasks associated with maintaining a Data Guard configuration. A fast-start failover to the target standby database fails. When restarting the databases, you may restart them in any order. The SHOW CONFIGURATION command will show you which databases can be reinstated and which databases must be re-created. 5. This guide uses the naming convention of appending an underscore followed by a letter to the db_name to create the db_unique_name. SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. It can be useful to perform such queries because fast-start failovers are fully automated and can occur at any time. SQL> Select Database_role from v$Database; Hi, I am working in IT industry with having more than 10 year of experience, worked as an Oracle DBA with a Company and handling different databases like Oracle, SQL Server , DB2 etc Metadata for the fuzzy snapshot is stored in the flashback log itself. If the primary database can be mounted, it may be possible to flush any unsent redo data from the primary database to the target standby database using the ALTER SYSTEM FLUSH REDO SQL statement. The subdirectories that DGMGRL creates under this directory will also have the observer computer is returned to you so that you can continue to During failover, bystanders "follow" the primary by default, flashing back and reapplying redo from the new primary as necessary. Without the credentials, Broker will complete the role transition, but will leave the databases in need of a manual restart. The observer host is 'observer.demo.org'. Once an observer is started, no further user interaction is required. Oracle 19c-Performing Dataguard Switchover Using DGMGRL Utility Overall commit latency is increased by the round-trip network latency. MASTEROBSERHOST TO command. only. 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. Alternatively, you can query the V$DATABASE view on the target standby database. The primary database was shut down without using the ABORT option. It is then configured to be active in the PHYSICAL_STANDBY role on the physical standby database SOUTH. Use the VALIDATE STATIC CONNECT IDENTIFIER command to ensure the static services have been configured correctly. SQL>select sequence#, applied from v$archived_log; failover to the target standby database. Add an entry to the oratab file for the standby, db1:/u01/app/oracle/product/11.1.0/db_1:Y. Step 4: Enable Fast-Start Failover Now we are ready to enable FSFO: DGMGRL> enable fast_start failover; Enabled in Zero Data Loss Mode. 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. The drain_timeout is specified in the SRVCTL You must set both The example assumes that the standby uses the same directory structure as the primary. This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. To override this behavior and allow a fast-start failover to occur if the observer is unable to contact the primary for more than FastStartFailoverThreshold seconds, set the ObserverOverride property to TRUE. Your email address will not be published. When you select a standby database to be the next primary database after a switchover or a failover, there are several factors to consider. 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. Data Guard. through these services to exit or for the specified wait time set the ObserverPingInterval and Enable Fast-Start Failover Using Cloud Control. See START OBSERVER IN BACKGROUND for more information Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. observer_hostname.log. Initiate the switchover on the primary database PRIM: PRIM>STARTUP MOUNT; You can use this information to identify ahead of time any redo transport configurations that would be incorrect after a role change, including any standbys that will not receive redo because the RedoRoutes property was not configured correctly. If an application has called this function and it has received a status of SUCCESS, then the master observer attempts a fast-start failover. If any errors occur during either conversion, the broker stops the switchover. On the Data Guard Failover Confirmation page, specify the type of failover that you want to perform: Complete: All available redo is applied on the standby database. 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. Add the SRLs. Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option. See Oracle Data Guard Concepts and Administration for more information on using the ALTER SYSTEM FLUSH REDO statement. To perform specified actions before or after a fast-start failover Then the STOP OBSERVER command can be issued successfully on the former master observer. Reset database properties related to Redo Apply services, such as DelayMins. 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). may allow the primary database to continue redo generation after Use the SQL ALTER DATABASE MOVE DATAFILE command to rename or relocate an online data file on a physical standby that is a fast-start failover target if the standby is mounted, but not open.
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