The standby VM (myVM2) has the Oracle software installed only. Open another prompt and connect to SQLPLUS: Broker Configuration Has Only One Registered Observer. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. Starting Observers as Background Processes. Errors occurring for any other configuration members will not impede the switchover. When the conditions for fast-start failover are met, the Broker adds messages to the observer log and broker log indicating that fast-start failover would have been initiated. Failovers become routine. After the patch has been successfully applied to all databases, take the following steps to enable fast-start failover and start the observer. To achieve Figure 6-2 shows the observer monitoring a fast-start failover configuration. No two observers on the same Data Guard Broker configuration can have the same name. However, there may be situations in which you must disable fast-start failover when If that metadata is pushed out, Oracle can no longer find a fuzzy snapshot so it will not be able to flash back. If the agent is not We'll start it interactively for now to verify that everything's working. Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_DG package. observers for a single Data Guard configuration. directory does not have the required permissions. The remaining Data Guard-related parameters will be set by Broker later in the walkthrough. DG_BROKER_START is set to TRUE and DG_BROKER_CONFIG_FILEn are set correctly SQL> sho parameter broker property. 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. To allow the master observer to automatically reinstate the former primary database, the database must be started and mounted. PeopleSoft can be configured for Active Data Guard. An spfile is required to persist these changes. Subdirectories within observers are registered, a directory named Failover automation ensures a seamless transition from the primary database to a synchronized standby database in cases of failure, while ensuring database availability by replaying uncommitted in-flight transactions. Setting it to 'FALSE' leaves the database open and stalled until it is terminated or signaled to proceed in the event a failover did not take place (e.g. Log into the new primary and verify that the changes made it across. If the new primary database was a primary database in the past, and had block Logical standby databases that are disabled during failover can be reinstated. To install Oracle Data Guard, you need to create two Azure VMs on the same availability set: The primary VM (myVM1) has a running Oracle instance. Configure the protection mode. Oracle Data Guard work on two database roles Primary and Standby. This is typically done for planned maintenance of the primary system. Don't initiate failover unless at least 30 minutes of history is available. 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. SWITCHOVER command, and the databases are managed by Oracle Reinstate the original primary database to act as a standby database in the new configuration. The simplest way to do this is to abort the primary. Once fast-start failover is enabled, the broker will ensure that fast-start failover The primary database can be opened even if there is no acknowledgement from the observer or target standby. configuration scripts and checks for errors or misconfigurations. When fast-start failover is enabled, the broker determines if a failover is necessary and initiates the failover to the current target standby database automatically, with no need for manual intervention. Reinstating the Former Primary Database in the Broker Configuration for more information about reinstatement. Conditions shown in blue are enabled by default. Note that the new primary database does not need to be restarted. Refer to the appropriate Oracle RAC or Oracle Restart documentation for further information. The observer configuration file is a text file and the syntax to define observers and groups is similar to that used in the listener.ora or tnsnames.ora files. SQL>SHUTDOWN IMMEDIATE; Initiate reinstatement by mounting the 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 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. See Installing and Starting the Observer. In the event of a Switch-over steps: Step-A: Shutdown primary database: SQL> shut immediate; Database closed. The broker disables all of the physical and snapshot standby databases in the configuration. Follow Smart way of Technology on WordPress.com. Failover:- In case of worst situation with data guard primary database, or not available for production than we can activated standby database as a primary production database. 1. Create or update the fast-start failover callout configuration file and include Use synonyms for the keyword you typed, for example, try "application" instead of "software.". the primary role, use the PreferredObserverHosts If this operation is successful, a zero data loss failover may be possible even if the primary database is not in a zero data loss protection mode. Determine the number and size of the Online Redo Log files (ORLs). Issue the following commands on Primary database and Standby database to find out: In maximum protection mode, an automatic failover is always possible because the During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. The command fails if the file does not exist. The foundation of FSFO is Data Guard - a primary and at least one standby. PRIM>STARTUP MOUNT; The playground: switch does not happen until the next time the primary contacts the target standby, Verify there are no active users connected to the databases. US Coast Guard Auxiliary. Steps for FAILOVER the Dataguard environment 1. The minimum value is 100 milliseconds. You can start, stop, and show observers for a group of configurations. been enabled on the database prior to the failover and there must be sufficient Displays only on the target standby database when it is SYNCHRONIZED with or is TARGET UNDER LAG LIMIT of the primary database, has connectivity to the observer, but the primary database does not have a connection to the observer. See Manual Failover for complete information about manual failovers. For reliable startup, the initial connection should always be made to the primary. database that has the least amount of unapplied redo (smallest apply lag). 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. configuration property specifies how frequently the observer Default value is 10 miliseconds. ConfigurationSimpleName. When this property is set to the default value of 0, it prevents the observer from periodically establishing a new connection with the primary database. command for more information about starting the A switchover guarantees no data loss. Do this prior to every failover test. 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. the current working directory, Uses standard output for displaying the observer logs. The list is empty by default. In this case, Flashback Database cannot be used to reinstate databases. Fast-start failover can be used only in a broker configuration and can be configured only through DGMGRL or Cloud Control. The reinstated database acts as the fast-start failover target for the new primary database, making a subsequent fast-start failover possible. ObserverConnectIdentifier allows you to specify different connect identifiers for the observer to use. In case of worst situation with data guard primary database, or not available for production than we can activated standby database as a primary production database. The FastStartFailoverLagLimit configuration property is only used by the broker when enabling fast-start failover for configurations operating in maximum performance mode. You can perform a manual failover even if fast-start failover is enabled. This document only talks about switchover involving physical standby database. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. 1. START OBSERVING [cfg_group_name] starts a new observer for each broker configuration in the specified group. 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. In such cases, the failed primary database is reinstated as a physical standby database. become the master observer. 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. 5. Oracle recommends that this property be set to a value that is small enough to allow timely detection of faults at the primary database, but large enough to limit the overhead associated with periodic observer connections to an acceptable level. . the names of the scripts created in the previous step. These FAN events can be used in the following ways: Applications can use FAN without programmatic changes if they use one of these Oracle integrated database clients: Oracle Database JDBC, Oracle Database Oracle Call Interface (OCI), Oracle Data Provider for .NET ( ODP.NET), or Universal Connection Pool for Java. For example: In the following example, assume the network between the primary database and the observer has failed. Select name,open_mode,database_role from v$database; Step:2 Cancel the MRP process If you re-create the old primary database, it must be created as the standby type of the old standby database. DGConnectIdentifier, "Scenario 9: Performing a Switchover Operation" for an example of using the VALIDATE DATABASE command to show a database's readiness to complete a role switchover, "Scenario 10: Performing a Manual Failover Operation" for an example of using the VALIDATE DATABASE command to show a database's readiness to complete a role failover. process. The broker initiates a failover after the number of seconds specified by this Choose a value high enough to avoid false disconnects from intermittent network trouble. FB Page:https://www.facebook.com/dbahariprasath/? Broker Configuration Has Multiple Registered Observers. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by the preferred method for starting an observer. It comes with a GUI and command line interface. If the designated fast-start failover target develops a problem and cannot be the target of a failover, then the broker automatically changes the fast-start failover target to one of the other candidate targets. In 10g, a single wallet can be used for multiple observers, but they must all use the same SYS password. All physical and snapshot standby databases will be disabled and must be re-created from a copy of the new primary database after a switchover to a logical standby database. Since the observer is a specialized instance of a dgmgrl session, the observer host should be installed with either the Oracle Client Administrator software or the full Oracle Database software stack. property. After a failover, a bystander will not automatically become the new failover target. (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. Initiate the failover on the standby database STAN: SQL>connect /@STAN as sysdba SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; 2. To help you select an appropriate switchover or failover target, use the following DGMGRL commands which perform checks on the database to determine its readiness to complete a role change. You can optionally indicate the database health conditions that should cause fast-start failover to occur. If the master observer detects an availability problem with the primary database, then it typically attempts to reconnect to the primary database within the time specified by the FastStartFailoverThreshold configuration property. FAN server-side callouts can be configured on the database tier. If the FastStartFailoverPmyShutdown configuration property is set to TRUE, then the former primary database will have been automatically shut down and must be manually restarted before the master observer can attempt to reinstate it. $DG_ADMIN/config_ConfigurationSimpleName/callout command is submitted successfully, the command-line prompt on the When you select a standby database to be the next primary database after a switchover or a failover, there are several factors to consider. 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. primary database. A number of prerequisites must be met on the primary in order to use Fast-Start Failover. This file is stored in the Failing over the database won't do much good if applications and other database clients don't know where the primary went. The syntax for the optional definition of a broker configuration group is: The group definition section is optional. 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. For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. The guide attempts to be operating system agnostic; however, some examples may contain platform specific elements such as path and file naming conventions. Archiver is unable to archive a redo log because the device is full or unavailable. Fast-start failover is faster when you take steps to optimize recovery so that the application of redo data to the standby database is kept up to date with the primary database's rate of redo application. This section describes how to configure an Oracle Net connect descriptor that meets this requirement. This article - the seventh in this ongoing . We'll leave the other properties at their default values for the walkthrough, but you should become familiar with all of the Broker config and database properties. Do not attempt to reinstate the old primary database if an ORA-752 or ORA-600 [3020] error has occurred at the failover target. A normal shutdown prevents a fast-start failover until the primary database and standby database are connected and communicating again. If you like a connect-time failover to survive across a data guard switchover, you need another way to do it. (Note: 11.1.0.7 adds the StaticConnectIdentifier Broker database property to allow you to specify a different service name.) In this mode, no actual changes are made to your Broker configuration. A broker configuration can belong to multiple groups. The services include switchover, switchback and failover. To configure fast-start failover in observe-only mode: Fast-start failover will not be triggered if the primary or standby database is shut down normally. For any work, queries and help. If the observer is unable to regain a connection to the primary database within the specified time, and the target standby database is ready for fast-start failover, then fast-start failover ensues. Automatic failover quickly and reliably fails over the standby Autonomous database to the primary database role, without requiring you to perform any manual steps. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. Alternatively, use the RedoRoutes property to configure the redo transport mode for the target standby and the database currently in the primary role. 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. The standby can be physical or logical and there can be multiple standbys, but only one of the standbys can be the failover target at any given time. DNS CNAME) that always resolves to the primary. These are some points to consider before you begin a switchover. This database property is used to specify how the observer should connect to and monitor the primary and standby database. Note that a switchover operation may be started before the specified wait What is true about Data Guard setup with fast-start failover? Maximum Availability mode uses synchronous redo transfer and FSFO imposes the additional requirement that the redo is recorded in the standby redo log (SRL) of the target standby (AFFIRM option of log_archive_dest_ n). configuration file, such as START OBSERVING, observer computer is returned to you so that you can continue to 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. Then, on the Fast-Start Failover Configure page, select the standby database that should be the target of a failover. In a separate terminal session, verify the configuration. This is cleared on both when the reinstatement has been completed. return until you issue the STOP OBSERVER command The following example displays the contents of the fast-start failover The most common problems are mismatched Data Guard protection modes and LogXptMode properties and forgetting to enable Flashback Database on the primary or standby. Fast-start failover will not be attempted for the other types of database shutdown (NORMAL, IMMEDIATE, TRANSACTIONAL). multiple, inexpensive servers is the basis for the failover and other fault-tolerance features that RAC provides. See Choosing a Target Standby Database for helpful advice. There are normally two situations when this operation will be performed: a planned outage for maintenance of the primary database or disaster recovery. Your email address will not be published. drain_timeout amongst the active services. commands. Complete Failovers in Configurations Using Far Sync Instances. In a manual failover, you convert a standby database to a primary database because the original primary database failed and there is no possibility of recovering the primary database in a timely manner. To see the specific parameter, use the "show database StatusReport" command. You can upgrade the protection mode later, if necessary, as described in Setting the Protection Mode for Your Configuration. For example: Fast-start failover occurs if both the observer and the target standby database lose connection to the primary database for the period of time specified by the FastStartFailoverThreshold configuration property. If they are isolated from each other, then you must first disable fast-start failover by using the FORCE option, and then stop the observer. LinkedIn:https://www.linkedin.com/in/hari-prasath-aa65bb19/ If fast-start failover is disabled, then manual failover may still be possible. Staff support, hardware and software, security (both software and site), network connections, and bandwidth should be equivalent at both sites. 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 Manual failover gives you control over exactly when a failover occurs and to which target standby database. This property cannot be used to prevent the primary database from shutting down if a fast-start failover occurred because a user configuration condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. Reinstatement restores high availability to the broker configuration so that, in the event of a failure of the new primary database, another fast-start failover can occur. irrespective of its content, indicates that the script executed successfully. The observer does not attempt to reinstate the former primary database. to set the time taken to detect a failure on the primary database: Set the FastStartFailoverThreshold FSFO can also be used with logical standbys and an FSFO-enabled configuration may have multiple standbys with a mix of physical and logical, but only one standby can be the failover target at any given time. When this property is set to NONE, the broker will disable all bystander standby databases without checking whether they have applied more redo data than the new primary database. REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. Fast-start failover quickly and reliably fails over the target standby database to the primary database role, without requiring you to perform any manual steps to invoke the failover. You can find detailed information about all observers, including master observers and backup observers, in the V$FS_FAILOVER_OBSERVERS view. the location of the observer log file, and the location of the observer runtime data Both Cloud Control and the DGMGRL CLI will do this automatically as part of failover. Instead, when broker notifies the Oracle However, no additional data is applied on the standby database once you invoke the failover. collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. Fast-start failover is enabled, but this standby database is not the target of the fast-start failover. You must also start and stop the SALESRO service on the primary so that it can be started on the standby. By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. the SYSDG or SYSDBA privilege. In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). The former primary database is disabled. The drain_timeout is specified in the SRVCTL A switchover is a role reversal between the primary database and one of its standby databases. Restore - Flashback Database restores the datafiles to the closest snapshot prior to the specified SCN. When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. If groups are not defined, you can still operate on all configurations defined in the file as a whole. under the $DG_ADMIN directory. /home1/dataguard/config_NorthSales/callout/fsfocallout.ora. Change Standby to Primary Database. If it exists, and it contains a pre-callout script location, On the Oracle Data Guard Overview page, click Database must be reinstated. if the observer is not running, The master observer and the target standby database are inconsistent with regard to the current state of the broker configuration, If the protection mode is maximum availability or maximum protection and the target standby database was not synchronized with the primary database at the time the primary database failed, If the protection mode is maximum performance and the apply point of the target standby database lags the redo generation point of the primary database by more than the amount specified by the FastStartFailoverLagLimit configuration property at the time the primary database failed. Broker can be configured to initiate failover on any of the following conditions. Use the callout configuration file and script status before the crash.