For example, to determine if fast-start failover can occur, the FS_FAILOVER_STATUS column displays either SYNCHRONIZED or TARGET UNDER LAG LIMIT and the FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. (Snapshot standbys are not included in the table because they are not supported as fast-start failover targets.). To start an observer as a background process, use the DGMGRL The master observer waits the number of seconds specified by the FastStartFailoverThreshold configuration property before attempting a fast-start failover when the primary database has crashed or has lost connectivity with the observer, as in the following situations: The primary database loses its connections with both the observer and target standby database. Problems with automatic reinstatement are frequently due to misconfiguration, so let's look at this in a bit more detail. If you are performing an immediate failover, then the database role is changed to primary without applying any accumulated redo data. You can switch back to the original Primary database later by performing another switch over. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by SQL>STARTUP; You cannot perform a manual failover to the target standby database for the same reason. Disaster Recovery with Oracle Data Guard - online presentation Set this property for the primary and target standby database if you want the observer to use a different connect identifier than that used to ship redo data (that is, the connect identifier specified by the DGConnectIdentifier property). The target standby database when it does not have connectivity with the primary database, fast-start failover is disabled only on the target standby database. These In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. Data Guard Broker Failover - DBA Genesis Support If the new primary database was a primary database in the past, and had block The broker preserves the protection mode that was in effect prior to the failover. *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 . (See Disabling Fast-Start Failover for important considerations when using the FORCE option.). Use the VALIDATE STATIC CONNECT IDENTIFIER command to ensure the static services have been configured correctly. 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. If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. 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. To issue commands and interact with the If you intend to switch back to the original primary database relatively soon, you may allow the physical and snapshot standbys to remain disabled. Instead, the old primary database must be re-created as a standby from a backup of the new primary using the procedure described in How to Re-create and Reenable a Disabled Database. Otherwise, they must be re-created from a copy of the new primary database. status before the crash. Running a StatusReport on the primary should verify that the error is due to a missing observer. In case of primary database failure, you will need to perform failover to transition the standby database to the primary role. The procedure for using RMAN to create a standby database is fully explained in Appendix F of Oracle Oracle Data Guard Concepts and Administration document (10g Rel 2 and 11g Rel 1). The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. It comes with a GUI and command line interface. Create a script to automate FSFO failover initiation and use it as your standard method for standby flips. 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). db_domain . To stop the observer when fast-start failover is disabled, the primary database must be running. In this mode, no actual changes are made to your Broker configuration. 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. have received all the redo data the primary has generated in order for automatic failover to Fast-Start Failover in Data Guard Environments on Oracle Cloud Don't initiate failover unless at least 30 minutes of history is available. Oracle Database 11g adds the ObserverConnectIdentifier database property to the Broker configuration, allowing you to specify a connect identifier for the observer to use for monitoring the primary and failover target. the observer was killed after the stall began, but before the failover timeout had elapsed). Step:5Bounce your database and verify database name its open mode and its role. must create a .suc and .err file in the PeopleSoft can be configured for Active Data Guard. In order to apply redo data to the standby database as soon as it is received, use Real-time apply. 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. To perform specified actions before or after a fast-start failover Other logical standby bystander databases in the broker configuration will remain viable after the switchover. 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). 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. SQL>SHUTDOWN IMMEDIATE; This section describes how to configure and verify each prerequisite. 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). occurred to the target standby database prior to disabling fast-start Failovers become routine. For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. 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. Albino DeSantis - Senior System Engineer - US Coast Guard - LinkedIn enabling fast-start failover. Improper Oracle Net configuration is a leading cause of reported FSFO issues. In a Managed Instance with multiple databases in Azure we can have high availability. Facebook:https://www.facebook.com/HariPrasathdba 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. Bystander standby databases that are not disabled by the broker after the switchover will continue operating in the state they were in before the switchover. is guaranteed to lose no more than the amount of alter system set standby_file_management=auto; This parameter must be set before the primary can be opened in Maximum Availability mode. If the primary database is an Oracle Real Application Clusters (Oracle RAC) database, the master observer will attempt to connect to one of the remaining primary instances. created under this directory by DGMGRL will also have the same permissions. The environment is a single instance database without any grid Infrastructure components. Startup can fail with "ORA-16647: could not start more than one observer" even when no observer is actually running if the previous observer process terminated without deregistering itself and the new observer isn't using the previous fsfo.dat file. Whether you reinstate or re-create a database depends on whether you performed a switchover or failover, on the type of standby database that was the target of the operation, and on whether or not there are sufficient flashback logs. Do this prior to every failover test. Determine the number and size of the Online Redo Log files (ORLs). PRIM>SHUTDOWN IMMEDIATE; Verify dmon process is running and broker parameters viz. required permissions, the admin folder is created A value of TRUE helps to ensure that an isolated primary database cannot satisfy user queries. This method will disable fast-start failover on all databases in the broker configuration. the preferred method for starting an observer. database is in the primary role. 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. distance. In the rare event that a switchover operation fails and you are left with no primary database, retry the switchover command. If fast-start failover is enabled, then a switchover can be performed only to the pre-specified target standby database and only if the standby database is synchronized with the primary database or is within the configured lag limit, for the max availability and max performance modes respectively. This allows Data Guard to remain functional during maintenance periods when the application listeners are down. When the configuration has only one registered observer, if the primary and target standby databases stay connected but the connection to the observer is lost, then the broker reports that the configuration is not observed. In this example, the original primary data is called PRIM and the original standby database is called STAN. 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. You must set both fast-start failover through Cloud Control. Follow the guidelines described in Choosing a 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. occur. are configured correctly. Therefore, the primary database can continue processing transactions, even if the target standby database fails. If the value is zero, the standby must Oracle 12c-Step by Step Manual Data Guard Switchover, Manual Upgrading Oracle Database From 11.2.0.4 to 12.2.0.1, Automatically Terminated The Blocking Session By Setting MAX_IDLE_BLOCKER_TIME, Apply Patching On Oracle 21c Database Release Update 21.7.0.0.0, Oracle 21c Point In Time Recovery of Pdb Database, Oracle 21c Cloning a PDB Database Using Sqldeveloper Tool. (Note: 11.1.0.7 adds the StaticConnectIdentifier Broker database property to allow you to specify a different service name.) file also declares broker configurations and defines configuration return until you issue the STOP OBSERVER command PDBs. Switchover/Failover operation in 2-node RAC and 2-node DATAGUARD 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 targets are referred to as candidate targets. After fast-start failover is enabled and up to four observers are started, one observer is nominated as the master observer that continuously monitors the environment to ensure the primary database is available. The broker first converts the original primary database to run in the standby role. These are the actions the broker performs after you start a switchover. 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. For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. If local_listener is already in use, add the Data Guard listener to the list. Broker changes database parameters during startup and role transitions via ALTER SYSTEM commands. You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. 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. Starting Observers as Background Processes. same permissions. Duplicate configuration names in configuration definitions are not allowed. 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. 1)What are the steps to do Switchover/Failover operation manually in 2-node RAC and 2-node DATAGUARD environment. Rather, fast-start failover will be enabled in accordance with the current protection mode. Instead, Oracle Clusterware opens PDBs on particular instances based on If the broker performs a switchover or failover, then it starts the service SALESRW or SALESRO based on the current role of the database. Observer sites monitor the fast-start failover environment. Add the wallet location and override to sqlnet.ora. All database connections associated with the observer, including the initial connection, must use dedicated server connections. After the fast-start failover completes successfully, the master observer will attempt to reinstate the former primary database as a new standby database when a connection to the former primary database is reestablished, and the FastStartFailoverAutoReinstate configuration property is set to TRUE. 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. 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. Now let's test switchover in the other direction. Refer to the appropriate Oracle RAC or Oracle Restart documentation for further information. value is 10. This Click Disable in the Fast-Start Failover wizard. 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. environment variable must have exclusive permissions wherein it can be accessed only The redo transport mode used to send redo to the target standby database or the database currently in the primary role. In maximum performance mode, the ability to automatically failover is restored So if the original Primary database is still accessible, you should always consider a switchover first. While Oracle 11g's Data Guard definitely protects a database when the entire production site is lost via its failover capabilities, it's still necessary for an Oracle DBA to intervene to complete the failover process. Note that enabling FSFO does not make the configuration ready for automatic failover - that requires an observer, which we'll get to next. Subdirectories within Examples of starting observers using DGMGRL are included in Scenario 6: Enabling Fast-Start Failover and Starting the Observer. A Senior Engineer's Guide to the System Design Interview 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 Databases that can be reinstated will have the following status value: For the REINSTATE command to succeed, Flashback Database must have The primary database must be running in order to start the observer. Now it will return PRIMARY. In this case, only observers on ob1-host and Verify the primary database instance is open. broker opens all the PDBs on the new primary database and on the target standby Implementing Oracle Data Guard Broker 19c in an Oracle Standby RAC Implement Oracle Data Guard on an Azure Linux virtual machine See Manual Failover for complete information about manual failovers. See Oracle Data Guard Concepts and Administration for more information on using the ALTER SYSTEM FLUSH REDO statement. Verify there are no active users connected to the databases. For example, perform full level 0 backups weekly and incremental level 1 backups daily. Broker can be configured to initiate failover on any of the following conditions. 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. Displays the current fast-start failover mode. DGMGRL. The string "NONAME" cannot be used as an observer name. In cases where After you click the Reinstate button, Cloud Control begins reinstating the database. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). This support note is available at http://support.oracle.com. time specified in the WAIT option. about starting the observer as a background Then set the configuration protection mode to maximum availability. Prerequisites for Enabling Fast-Start Failover provides complete information about all of the fast-start failover and reinstatement requirements. These conditions are described in the following table: Dictionary corruption of a critical database. The log file name is specified with the LOGFILE IS option of the START OBSERVER command. This guide uses the naming convention of appending an underscore followed by a letter to the db_name to create the db_unique_name. 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. 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. list of the observers that can become the master observer when that become the master observer. Fast-Start Failover in Oracle 11g Data Guard - Database Journal Once you set these properties, their values persist through role changes during switchover and failover. ob2-host can be a master observer when However, fast-start failover cannot occur when the target standby database is in an unobserved state. Event notification and database connection failover support is available to database clients connected to local database services when a broker-managed failover occurs. In order to fully automate switchover, Broker needs SYSDBA credentials in order to restart one or both databases. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. After a role change, the naming service can be updated with the new primary's address. Switchover Steps. 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 . If the former primary database cannot be reinstated automatically, you can manually reinstate it using either the DGMGRL REINSTATE command or Cloud Control. After the restart, Redo Apply begins applying redo data from the new primary Note: the FSFO observer version must match the database version. from another DGMGRL session. configuration named ConfigurationSimpleName. Oracle Data Guard Command-Line Interface Reference for more information about these broker commands. 8.2 Private Cloud Appliance and . Data Guard | Oracle The connect descriptor can be configured in one of two ways: Oracle Database PL/SQL Language Reference for more information about the DB_ROLE_CHANGE system event. If all the databases do not have the same values, SRVCTL attempts to override the values, which will fail on the physical standby database because it is open read-only. SHOW OBSERVERS [FOR fg_group_name ] shows information about observers for all configurations in the specified group. If automatic reinstatement fails, the broker will log errors and the former primary database will remain in the mounted state. An observer is a separate OCI client-side component that run on a different computer from the primary and standby databases and monitors the availability of the primary database. In an environment where there are multiple observers configured, stopping the master observer is not allowed unless it is the last running observer. Reenabling Disabled Databases After a Role Change describes how to restore their viability as standby databases. 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 file The broker selects a target based on the order in which they are specified on the FaststartFailoverTarget property. By default, the observer will initiate failover to the target standby if and only if ALL of the following are true: Oracle Database 11g Rel 1 introduced user configurable failover conditions that can trigger the observer to initiate failover immediately. Which three are prerequisites for enabling fast-start failover This is the recommended method for disabling fast-start failover. For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. Data Guard. Apply services on all other bystander standby databases automatically begin applying redo data received from the new primary database. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. To stop the observer, see Stopping the Observer. /home1/dataguard/config_NorthSales/callout/fsfocallout.ora. Set the FastStartFailoverThreshold property to specify the number of seconds you want the observer and target standby database to wait (after detecting the primary database is unavailable) before initiating a failover. With FSFO enabled, Broker expects to find an observer, which we haven't started yet, so if you verify the at this point with 'show configuration', Broker will report a warning (if it doesn't, give it a minute to discover that the observer isn't there). 12c Dataguard, In 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. Create a unique connect alias for each database. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. The current primary database must have its LogXptMode property set accordingly and must have standby redo logs configured. There are two types of failover operations: Graceful or "no-data-loss" failover and Forced or "minimal-data-loss" failover. We'll start it interactively for now to verify that everything's working. SET ObserverConfigFile used to specify a customized observer configuration file. Alternatively, you can query the V$DATABASE view on the target standby database. Let's run the command on the primary database to validate if the environments are ready for the role transition : JITPRD> alter database switchover to JITSDB verify; alter database switchover to JITSDB verify * ERROR at line 1: ORA-16475: succeeded with warnings, check alert log for more details Specifying Preferred Observers Based on Current Primary. guaranteed to lose no data. An existing connection which is already closed from the database side would throw an error. Initiate the switchover on the primary database PRIM: Provides an automatic failover environment that If the primary or target standby databases lose connections to all backup observers, then the broker does not try to nominate a backup observer as the new master observer, and the broker reports that the configuration is not observed. Such preparation includes: Ensuring that standby redo log files are configured on the primary database.
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