Setting this property to 'TRUE' (the default) causes the primary to self-terminate. Oracle Data Guard Concepts and Administration provides information about setting up the databases in preparation of a switchover. alter database recover managed standby database finish; alter database activate standby database; Managed recovery process has been stopped between primary and standby database and standby becomes primary database. After setting local_listener, register the database with the listener and verify the services have been registered. Displays if the standby database's redo applied point lags 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. This allows Data Guard to remain functional during maintenance periods when the application listeners are down. These facilities allow applications written to take advantage of them to receive asynchronous notification of database events, including role transitions. This allows for redundancy in your Data Guard observer setup as well. After the database has been re-created, enable broker management of the re-created standby database by using the DGMGRL ENABLE DATABASE command. Oracle Data Guard can switch a standby database to the primary role in case a production database becomes unavailable due to . Configure Data Guard Broker to manage and monitor the Data Guard configuration. DG_ADMIN environment variable is not set, the files are stored in For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. A snapshot standby cannot be the target of a switchover or fast-start failover operation. As a result, there is no guarantee that the observer will not perform a fast-start failover to the target standby database if the observer determines that conditions warrant a failover. If only a path is specified, the files are Reenabling Disabled Databases After a Role Change describes how to restore their viability as standby databases. 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. Issue the following commands on Primary database and Standby database to find out: It has two parts in the following order: Configuration declaration this section is mandatory. An observer is an OCI The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. It doesn't consider how much of that redo has been applied. If the protection mode was at maximum protection, it is reset to maximum performance. The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. PRIM>SHUTDOWN IMMEDIATE; You can also switch the master observer hosts for a group of configurations to one specific host. The connect-identifier is a TNS alias defined in tnsnames.ora through which all instances of all databases in this Data Guard broker configuration can be reached. 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. Some of the statistics that can be monitored are as follows: LAST_FAILOVER_TIME that shows the timestamp of last fast-start failover, LAST_FAILOVER_REASON that shows the reason for the last fast-start failover. specified by the ObserverPingInterval property. command on the observer computer: The observer is a continuously executing process that is FastStartFailoverLagLimit configuration property is set to zero) or The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. To stop the observer, see Stopping the Observer. It comes with a GUI and command line interface. database. *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 . The command SHOW OBSERVER provides detailed information about registered observers. If groups are not defined, you can still operate on all configurations defined in the file as a whole. However the target can receive redo from a far sync instance.). The broker allows the failover to proceed as long as there are no errors for the standby database that you selected to participate in the failover. ERROR: Unable to verify the graphical display setup. 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. In a Data Guard environment primary database is open in read write mode and the standby database in read only mode for reporting purpose. 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 the use of "/@" to login using the wallet. It uses the connect identifier specified in the observer configuration file to locate the credentials for a broker configuration from the Oracle wallet. Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. To avoid problems due to timing variations, values less than 60 minutes are not recommended and values of 30 or less virtually guarantee Flashback Database failure. If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. 3. When performing a failover in a configuration whose standbys are all of the same type, choose the standby database that has the smallest transport lag. Initiate reinstatement by mounting the database. Create a wallet and set the default username and password to the database's SYSDBA credentials (usually SYS). See the Oracle Maximum Availability Architecture technical briefs at: When setting the FastStartFailoverLagLimit configuration property, consider these tradeoffs between performance and potential data-loss: A low lag limit will minimize data loss but may impact the performance of the primary database. For this build, we will use a single physical standby database. Client-side broker 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. A running observer will follow the primary automatically after a role transition, but a newly (re)started observer won't start if the initial connection is to a down database or one with an out of date or corrupted Broker config file. The FastStartFailoverTarget configuration property on the primary unless the new property value contains the current fast-start failover target. Improper Oracle Net configuration is a leading cause of reported FSFO issues. This results in the observer establishing a new connection to the primary database every 30 seconds. Immediate: No additional data is applied on the standby database, resulting in a data-loss . Worked as a Development and Database Administrator. 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. 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. But it will also continue trying to reconnect to the primary database indefinitely. The NetTimeout property specifies the number of seconds LGWR will block waiting for acknowledgment from the standby in synchronous mode before considering the connection lost (corresponds to the NET_TIMEOUT option of log_archive_dest_n). (See Disabling Fast-Start Failover for important considerations when using the FORCE option.). lower detection times for primary database failures. It is very much useful, when the organization has multiple standby sites. Use synonyms for the keyword you typed, for example, try "application" instead of "software.". Among many benefits of using this utility, I highlight that while using it, it will not need manual intervention to recover the databases or eventually a switchover in case the primary database becomes unavailable. This section describes how to stay on top of your FSFO environments. A failover is a role transition in which one of the standby databases is transitioned to the primary role after the primary database (all instances in the case of an Oracle RAC database) fails or has become unreachable. miliseconds. To optimize the log apply rate: Do not configure the DelayMins database property to delay applying archived redo log files to the standby database (see Managing Log Apply Services for more information). 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. This section lists the steps the master observer takes to determine if a fast-start failover is needed and then to perform one, if necessary. The following sections describe how to reinstate or reenable a database. failover to the target standby database. The steps in this section describe the tasks involved to perform a manual failover. ensure that it has the required permissions. This property allows you to specify a priority ordered If the primary database has multiple standby databases, then you can specify multiple fast-start failover targets, using the FastStartFailoverTarget property. STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. Oracle recommends configuring Flashback Database on every database so that if failover occurs to a physical standby database, you can more easily reinstate any disabled standby databases. Such preparation includes: Ensuring that standby redo log files are configured on the primary database. If the group name is not provided, then a new observer is started for each broker configuration defined in observer.ora. The Oracle Database 10g FSFO observer is limited to using the default username and password defined in the wallet. Bystander standby databases may be disabled by the broker during the failover, and they must be reinstated or re-created before they can serve as standby databases to the new primary database. The broker disables all of the physical and snapshot standby databases in the configuration. files include the observer configuration file (observer.ora), observer log If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. OBSERVER command, if this directory does not have the Use the wrapper script to start the observer process when the observer host boots or to restart it if it dies. using the same SYS credentials you used when you connected to the 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. In this case fast-start failover cannot occur because the databases are not ready to failover. A failover may or may not result in data loss depending on the protection mode in effect at the time of the failover. If automatic reinstatement fails, the broker will log errors and the former primary database will remain in the mounted state. See Oracle Data Guard Concepts and Administration for more information on using the ALTER SYSTEM FLUSH REDO statement. Fast-start failover is inhibited in this case. The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. 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. prolonged stall, either the observer or target standby database After a switchover completes, the broker preserves the overall Oracle Data Guard protection mode as part of the switchover process by keeping the protection mode at the same protection level (maximum protection, maximum availability, or maximum performance) it was at before the switchover. After step 1 finishes, Switch the original physical standby db STAN to primary role; Enabling Fast-Start Failover describes how to start observers as a part of the step-by-step process to enable fast-start failover. change tracking enabled, broker enables block change tracking on the new If you are performing a complete failover, then all accumulated redo data is applied before the database role is changed to primary. All database connections associated with the observer, including the initial connection, must use dedicated server connections. If fast-start failover is enabled and the Datafile Write Errors condition is specified, then a fast-start failover is initiated if write errors are encountered in any data files, including temp files, system data files, and undo files. Fast-start failover will not be attempted for the other types of database shutdown (NORMAL, IMMEDIATE, TRANSACTIONAL). DGMGRL. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. If there is more than one standby database in the configuration, you must explicitly set the FastStartFailoverTarget property on the primary database to name one or more candidate target standby databases. The logs also contain other details about the actions that will be performed in case of a failover. Specifying the Observer Configuration File. If a single-instance primary database (either Oracle RAC or non-Oracle RAC), or if all instances of an Oracle RAC primary database fail, the observer attempts a fast-start failover. observer name, host, whether it is the master observer, when it became the master 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 such cases, the failed primary database is reinstated as a physical standby database. Table 6-2 FS_FAILOVER_STATUS Column of the V$DATABASE View. Switchover and Manual Failover for more information about switchovers and manual failovers, respectively. 2. Oracle Data Guard work on two database roles Primary and Standby. Enabling fast-start failover does not trigger a failover. 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. The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. To start an observer as a background process, use the DGMGRL from another DGMGRL session. Before stopping an observer, note the following: The observer does not stop immediately when you issue the STOP OBSERVER command. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: Issue the DISABLE FAST_START FAILOVER command or the DISABLE FAST_START FAILOVER FORCE command. variable must have read, write, and execute permissions for the directory owner Data Guard broker does not manage or store credentials. Simply use DISABLE FAST_START FAILOVER. Reinstate the former primary database as a new standby database. ObserverConfigFile is a DGMGRL session runtime property. Check the Undo tablespace Usage in Oracle, Exclude/Include option in EXPDP and IMPDP Datapump, Missing Dependencies Python Core / win32api, Stop the EXPDP/IMPDP Datapump Job in Oracle, Find the temp usage by sessions in Oracle, Create & grant permission to directory in Oracle, Check the Patch Applied to the Oracle Database. Standby databases not involved in the switchover (known as bystander standby databases) continue operating in the state they were in before the switchover occurred and will automatically begin applying redo data received from the new primary database. 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. Each group that you define must have at least one broker configuration. file also declares broker configurations and defines configuration The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. Install the DGMGRL command-line interface on the observer computer as described in Oracle Data Guard Installation. This is called failover. Add an entry to the oratab file for the standby, db1:/u01/app/oracle/product/11.1.0/db_1:Y. This lets you take advantage of the broker's For example, if the limit specified is 30 seconds (the default), FSFO guarantees that all transactions that committed prior to 30 seconds ago are preserved during failover. After the patch has been successfully applied to all databases, take the following steps to enable fast-start failover and start the observer. If a single-instance primary database (either Oracle RAC or non-Oracle RAC), or if all instances of an Oracle RAC primary database are shut down with the ABORT option, the observer attempts a fast-start failover. receives redo data from a far sync instance. occur. Before enabling fast-start failover, use one of the following techniques primary, only the observers specified in the property can be use in the SET Immediate Failovers in Configurations Using Cascaded Standbys. The configuration and database status report that the observer is not running and return one of the following status messages: While the configuration is in the unobserved state, fast-start failover cannot happen. 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). This section describes how to configure and verify each prerequisite. Here's a one-liner observer startup for *nix. You must set both STANDBY> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; Verify there are no active users connected to the databases. Complete Failovers in Configurations Using Far Sync Instances. The service can be started on the physical standby only after the redo generated by starting the service has been applied. Reinstatement of the failed primary database as a new standby database failed. The observer host is 'observer.demo.org'. If the primary and target standby databases do not have network connectivity or if the database to which you are connected does not have network connectivity with the primary database, consider using DISABLE FAST_START FAILOVER with the FORCE option. 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. db_domain . 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. To get started, all you'll need is Oracle Database Enterprise Edition Release 10.2 or later, a database, and three hosts: two for the databases and a small host for the FSFO observer. 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. Overview of Switchover and Failover in a Broker Environment. The string "NONAME" cannot be used as an observer name. 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. It's a good idea to have at least two hosts configured to run observers so that one can take over if the other fails. 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. See Sources of Diagnostic Information for details about the broker's drc* log files. Disabling fast-start failover does not stop the observer. The primary database must be running in order to start the observer. If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. Learn how to use Oracle Data Guard broker to manage databases during switchover and failover. 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. To stop the observer when fast-start failover is enabled, the primary database and target standby database must be connected and communicating with each other. If the standby database is not enabled for management by the broker, then the failover cannot occur. Relationship Between Primary, Target Standby, and Observer During Fast-start Failover. If the configuration contains physical, snapshot, and logical standby databases, consider choosing a physical standby database as the target standby database.