data guard failover steps data guard failover steps

observer. We'll start it interactively for now to verify that everything's working. Oracle Data Guard 11gr2 Administration Beginner S Guide As recognized, adventure as well as experience practically lesson, amusement, . The former primary database is disabled. If the former primary database cannot be reinstated automatically, you can manually reinstate it using either the DGMGRL REINSTATE command or Cloud Control. A failover to a logical standby database requires that all physical and snapshot standby databases be re-created from a copy of the new primary database after the failover completes. Use Recovery Manager (RMAN) to back up the PeopleSoft database on a regular backup schedule. There may or may not be data loss depending upon whether your primary and target standby databases were synchronized at the time of the primary database failure. Starts redo transport services to begin transmitting redo data to all bystander standby databases that were not disabled. Oracle Data Guard Concepts and Administration provides information about setting up the databases in preparation of a switchover. https://www.facebook.com/dbahariprasath/? Once you have completed the switchover back to the original primary, you may then reenable the physical and snapshot standby databases since they are still viable standbys for the original primary database. observer on ob1-host will be given priority over For a system to process an instruction involving data access, these are the certain steps involved: Fetch the block of data from the hard disk (secondary/permanent storage) to the primary memory (e.g. The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. 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. The broker allows a complete failover to proceed as long as there are no errors present on the standby database that you selected to participate in the failover. Then, click Continue to proceed to the next page. After 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. Read-Only Standby and Active Data Guard commands. Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. operation. Then, on the Fast-Start Failover Change Mode page, click Enabled. The broker controls the rest of the switchover. create the directory specified by the DG_ADMIN environment variable and Figure 6-2 shows the observer monitoring a fast-start failover configuration. Performing failover : Step 1: Check Standby Database role. required permissions, DGMGRL reports an error. This lets you take advantage of the broker's You must specify it every time you start a new DGMGRL client. The observer persistently maintains information about the fast-start failover configuration in a binary file created in the working directory where you started the observer. An observer is an OCI ORACLE instance shut down. Without the credentials, Broker will complete the role transition, but will leave the databases in need of a manual restart. Before stopping an observer, note the following: The observer does not stop immediately when you issue the STOP OBSERVER command. If it detects that Flashback Database was disabled, either manually, or automatically because Flashback Database discovered a problem, Broker signals "ORA-16827: Flashback Database is disabled". isolated. The "Configuring Authentication" chapter of the Oracle Database Security Guide provides detailed instructions for creating a wallet. This walkthrough uses Maximum Availability mode to achieve "zero data loss". Before a 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). Note that the new primary database does not need to be restarted. The primary database can be opened even if there is no acknowledgement from the observer or target standby. When you execute commands that affect multiple observers, if you have not specified a name and location for the observer configuration file, then broker searches the current working directory for a file named observer.ora. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. are configured correctly. To see the specific parameter, use the "show database StatusReport" command. It must appear as the first part of an observer configuration file. command for more information about starting the orapwd file=$ORACLE_HOME/dbs/orapw$ORACLE_SID. This is true regardless of the settings for the FastStartFailoverPmyShutdown and FastStartFailoverAutoReinstate configuration properties. The VALIDATE FAST_START FAILOVER command parses the callout Alternatively, if you intend to switch back to the original primary relatively soon, then you may re-enable the disabled standby databases after the switch back. Remember to check Flashback Database history before aborting the primary. To maintain a viable disaster-recovery solution in the event of another disaster, you may need to perform additional steps. directory does not have the required permissions. In command does not have a network connection to the primary database. The example below takes advantage of the 11g RMAN Active Database Duplication feature. In addition, a logical standby database may contain only a subset of the data present in the primary database. All standbys other than the failover target are considered bystanders (v$database.fs_failover_status = 'BYSTANDER'). If the configuration contains both physical and logical standby databases, consider choosing a physical standby database (that has the least amount of unapplied redo) to be the target standby database. SQL> Select Database_role from v$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 For Oracle Database Release 12.2 and higher, Oracle Enterprise Manager Cloud Control (Cloud Control) supports configuring multiple observers using the Enterprise Manager Command Line Interface (EM CLI). list of the observers that can become the master observer when that SQL>STARTUP; In 10g, a single wallet can be used for multiple observers, but they must all use the same SYS password. Failing over the database won't do much good if applications and other database clients don't know where the primary went. 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. The broker selects a target based on the order in which they are specified on the FaststartFailoverTarget property. Although the default value of 30 seconds is typically adequate for detecting outages and failures on most configurations, you can adjust failover sensitivity with this property to decrease the probability of false failovers in a temporarily unstable environment. If the client uses remote ONS subscription, the client must specify the hostname and port of the ONS daemon(s) of the primary database and each standby database. Oracle Data Guard configuration with DGMGRL. lower detection times for primary database failures. property. SQL> startup ORACLE instance started. alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. Configure Data Guard Broker to manage and monitor the Data Guard configuration. To failover, connect to the standby database and use the DGMGRL FAILOVER TO db-unique-name command. If the target is a snapshot standby database, the broker first converts the database to a physical standby database. configuration named ConfigurationSimpleName. If you want to use one Oracle home to start multiple observers, with each observer monitoring a different fast-start failover configuration, use the FILE qualifier to specify a unique observer configuration file location for each configuration to be monitored. Enabling Fast-Start Failover Task 1: Determine Which of the Available Standby Databases is the Best Target for the Failover, Enabling Fast-Start Failover Task 2: Specify Target Standbys with the FastStartFailoverTarget Configuration Property, Enabling Fast-Start Failover Task 3: Determine the Protection Mode You Want, Enabling Fast-Start Failover Task 4: Set the FastStartFailoverThreshold Configuration Property, Enabling Fast-Start Failover Task 5: Set Other Properties Related to Fast-Start Failover (Optional), Enabling Fast-Start Failover Task 6: Enable Additional Fast-Start Failover Conditions (Optional), Enabling Fast-Start Failover Task 7: Using DGMGRL or Cloud Control, Enabling Fast-Start Failover Task 8: Start the Observer, Enabling Fast-Start Failover Task 9: Verify the Fast-Start Failover Environment. After you click the Reinstate button, Cloud Control begins reinstating the database. In case of primary database failure, you will need to perform failover to transition the standby database to the primary role. If possible, confirm that fast-start failover has not Clusterware: The broker notifies Oracle Clusterware to stop active Improper Oracle Net configuration is a leading cause of reported FSFO issues. There are prerequisites that must be met before the broker allows you to enable fast-start failover. You can optionally indicate the database health conditions that should cause fast-start failover to occur. On the new primary database STAN, perform a SWITCH LOGFILE to start sending redo data to the standby database PRIM. Please contact us at [email protected]. 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. The observer is the key element that separates Data Guard failover from its pre-FSFO role as the plan of last resort to its leading role in a robust high availability solution. may allow the primary database to continue redo generation after Now it will return PRIMARY. Oracle Data Guard work on two database roles Primary and Standby. On the Oracle Data Guard Overview page in Cloud Control, select the standby database that you want to change to the primary role and click Failover. This example shows the verbose mode of the 'show configuration' command that provides FSFO-specific information. The observer is very lightweight, requiring few system resources. Displays the current fast-start failover mode. Immediately after issuing command in step 2, shut down and restart the standby instance STAN: Metadata for the fuzzy snapshot is stored in the flashback log itself. In this mode, the FastStartFailoverLagLimit configuration property is set to zero. ob2-host can be a master observer when They can all be done at the same time in a single bounce. Flashback Database stores its logs in the Flash Recovery Area (FRA), so the FRA must be large enough to store at least 60 minutes of Flashback Database history. Here's a one-liner observer startup for *nix. configuration property. This feature increases the availability of your database in the event of a disaster by reducing the need for you to perform a failover operation manually. 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. 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. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. It is then started and stopped on the primary database. To stop the observer, see Stopping the Observer. If the Oracle Data Guard configuration is operating in maximum protection mode, the broker does not allow a switchover to occur to a logical standby database. prolonged stall, either the observer or target standby database the location of the observer log file, and the location of the observer runtime data If the DG_ADMIN environment variable is not defined, or the Oracle Data Guard Broker is a utility that can help you manage your Oracle Data Guard. Use the 'show fast_start failover' command to see which user configurable FSFO failover conditions are in effect. One is the master 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. 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. If the observer finds that the database is no longer the primary, it will attempt to reinstate it as the failover target standby. The FS_FAILOVER_STATUS column in the V$DATABASE view for the target standby database displays a reason why fast-start failover cannot occur. If the specified log file is not accessible, or the LOGFILE IS option is not used, then the observer output is sent to standard output. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. Verifies that the primary and the target standby databases are in the following states: The primary database is enabled and is in the TRANSPORT-ON state. The existence of a .suc file, In a manual failover, you convert a standby database to a primary database because the original primary database failed and there is no possibility of recovering the primary database in a timely manner. Then set the configuration protection mode to maximum availability. In previous releases, OCI and ODP.NET clients receive FAN notifications via Oracle Advanced Queuing (AQ). Default value is 100 It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. The v$database view has has columns specifically for monitoring FSFO status. Most of the network services used in a FSFO environment may use dynamic registration, but to enable Broker to restart instances during role transitions or during reinstatement after a failover, you must define a static service named db_unique_name_dgmgrl. If Flashback Database was enabled on the primary database.If not, the whole setup process must be followed, but this time using the original primary server as the standby. 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. Only the observer can initiate FSFO failover. Moorestown, New Jersey, United States. Verify Before Switch-over: To switchover to a standby that is not the current failover target: John Smiley [[email protected]] is a persistent storage architect for a major online retailer. (Note that the target standby cannot be a far-sync instance. There can be up to four failure on the primary database. When the process is complete, the database will be enabled as a standby database to the new primary database, and Cloud Control displays the Oracle Data Guard Overview page. You can issue a Switch-over steps: Step-A: Shutdown primary database: SQL> shut immediate; Database closed. Specifying the Observer Configuration File. If the configured data loss guarantee cannot be upheld, If fast-start failover is 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 the START OBSERVER command for more information. Valid values are >= 10. stored in the specified path using the default file names. In the rare event that a switchover operation fails and you are left with no primary database, retry the switchover command. Observer uses the value of the DGConnectIdentifier property to connect to and monitor the primary and target standby databases. To prevent automatic reinstatement of the former primary database in these cases, set this configuration property to FALSE. Managed recovery process has been stopped between primary and standby database and standby becomes primary database. Keep this trigger as simple and reliable as possible, limiting it to only what is absolutely necessary at the moment of role transition, since any failures at this point may affect availability. 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. fast-start failover, you can issue the DGMGRL SHOW FAST_START FAILOVER, failover configuration file, this script is run. If a bystander standby database is not disabled by the broker during this failover, it will remain in the state it was in before the failover. 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. In Oracle RAC configurations, the Inaccessible Logfile and Stuck Archiver health conditions may only be applicable to a single instance. irrespective of its content, indicates that the script executed successfully. To start an observer, you must be able to log in to DGMGRL with an account that has If client-side ONS configuration is used, the client-side ONS configuration file must specify the hostname and port of the ONS daemon(s) of the primary database and each standby database. 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. STOP OBSERVING [cfg_group_name] stops LOCAL observers running on this host (where this DGMGRL is running) for all broker configurations in a specified group. If no name is specified for the observer then a default observer name, the host name of machine where the START OBSERVER command is issued, is used. For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. Broker Configuration Has Only One Registered Observer. If the standby database is not enabled for management by the broker, then the failover cannot occur. Now it will return PRIMARY. Group definition this section is optional. DGMGRL can be used to manage multiple observers in a group of broker configurations. Initiate the switchover on the primary database PRIM: 5. The broker disables all of the physical and snapshot standby databases in the configuration. lose no more than the amount of data (in seconds) specified by the Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. For example, perform full level 0 backups weekly and incremental level 1 backups daily. Be sure to include the Data Guard listener in the local_listeners database parameter. To proceed, you must first disable fast-start failover using the FORCE option, and then perform a manual failover. You can, however, perform a manual failover to a snapshot standby. Except for testing purposes, it is not recommended that you start more than one observer on the same host for a Data Guard broker configuration. For example, if a physical standby database was in the APPLY-OFF state, it will remain in the APPLY-OFF state. When you configure data guard using OCI console, the default mode is set to maxprotection. The default group is all the configurations defined in the observer configuration file. Any broker configuration name that is referred to must exist in the configuration declaration section. this directory are used to store the files related to the DGMGRL. The terminal session will appear to hang at this point. See Reenabling Disabled Databases After a Role Change. This allows for redundancy in your Data Guard observer setup as well. The broker reinstates bystander standby databases that were disabled during a failover as standby databases to the new primary database. If you initiated a complete failover and it fails, you might need to use immediate failover. For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. 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. The minimum detection time is 6 seconds, which is the default Flashback Database records the before-image of changed blocks. become the master observer. Once the Oracle instance is transitioned into primary database status in either switchover or failover, the life of the database as the standby ends and its service as the primary database . failover to the target standby database. It is also possible to initiate failover using the dgmgrl failover command. enabling fast-start failover. 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. Oracle Real Application Clusters Administration and Deployment Guide for information about Application Continuity, The broker simplifies switchovers and failovers by allowing you to invoke them using a single key click in Oracle Enterprise Manager Cloud Control (Cloud Control) or a single command in the DGMGRL command-line interface (referred to in this documentation as, Ensure that the standby database you choose to be the target of fast-start failover has its, Oracle Data Guard Concepts and Administration.