This 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. Determines whether or not any standby databases that did not participate in the failover operation have applied redo data beyond the new primary database, and thus need to be disabled. 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. 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. See the Cloud Control online help for more information. receives redo data from a far sync instance. Using Cloud Control, you can view the value of the ApplyLag column for each standby database in the Standby Databases section of the Oracle Data Guard Overview page. It will return PHYSICAL STANDBY, The default Install the DGMGRL command-line interface on the observer computer as described in Oracle Data Guard Installation. These clients can be configured for Fast Connection Failover (FCF) to automatically connect to a new primary database after a failover. The steps in this section describe the tasks involved to perform a manual failover. POTENTIAL DATA LOSS: Fast-start failover is enabled with some data loss. Create a pre-callout script, or a post-callout script, or both. by the current operating system user who is running DGMGRL The subdirectories You must re-create the database manually from a copy of the current primary database and then reenable the database in the broker configuration. Database hosts are referred to as "a" and "b" hosts and the databases themselves are referred to as the "a" and "b" databases. Issue the following command while connected to any database in the broker configuration, except the database that is to be reinstated: The newly reinstated standby database will begin serving as a standby database to the new primary 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. The broker reinstates a failed primary database as a standby database of the same type (physical or logical standby database) as the old standby database. To verify this change, again query the Database_role column of V$DATABASE. You must determine which available standby databases should be targets for failover. You must specify it every time you start a new DGMGRL client. 1 second. The failover was to a logical standby database. The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. The following example shows you how to set up more than one service on a database and how using the broker ensures that the correct service starts on the correct database. In the rare event that a switchover operation fails and you are left with no primary database, retry the switchover command. If fast-start failover is REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. We want the observer to be able to automatically reinstate the former primary as a standby after our failover tests, so before each test, make sure that Flashback Database has at least 30 minutes of history. You can manually stop a specific observer or all observers. Set the, Configure the connect descriptor with a single network name that is registered with a global naming service such as DNS or LDAP. The broker preserves the protection mode that was in effect prior to the failover. Although redo transfer is synchronous, Maximum Availability mode allows the primary to remain available if the standby database becomes unavailable for any reason (e.g. For example: You can find information about the master observer by querying the V$DATABASE view. Oracle 11g Manual Data Guard Part-II - DBAtricksWorld.com Both Cloud Control and the DGMGRL CLI will do this automatically as part of failover. 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. 3. ORACLE instance shut down. directory does not have the required permissions. This configuration property causes the former primary database to be automatically reinstated if a fast-start failover was initiated because the primary database was either isolated or had crashed. This results in the observer establishing a new connection to the primary database every 30 seconds. This not only saves time and minimizes problems by automating an otherwise manual process, it exercises your failover and DR procedures with every flip so that you know the FSFO configuration is sound and, in a real emergency, everyone knows what to do. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . See Manual Failover for information about manual failover. If a fast-start failover was initiated because the primary database had crashed or lost connectivity with the master observer and target standby database, then the master observer automatically attempts to reinstate the former primary database as a standby database, if the FastStartFailoverAutoReinstate configuration property is set to TRUE. Configure the TNSNAMES.ORA file on the observer system so that the observer is able to connect to the primary database and to the pre-selected target standby database. The default group is all the configurations defined in the observer configuration file. Set both these properties to achieve a primary failure detection time of 1 By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. The former primary database is disabled. A value of TRUE helps to ensure that an isolated primary database cannot satisfy user queries. $DG_ADMIN directory. SQL>ALTER SYSTEM SWITCH LOGFILE; Time for action - using interfaces to monitor Data Guard; Other replication solutions and Data Guard; Now it will return PRIMARY. The target standby database is synchronized with the primary database if it is a configuration operating in maximum availability or maximum protection mode, or the target standby database is within the lag limit if it is a configuration operating in maximum performance mode. Disabling fast-start failover with the FORCE option when connected to the target standby database guarantees that fast-start failover will not occur. become the master observer. Disabling Fast-Start Failover Using Cloud Control. When the configuration has more than one registered observer, if the primary and target standby databases stay connected but the connection to the master observer is lost, then the broker tries to nominate a backup observer as the new master observer. 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. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. configuration scripts and checks for errors or misconfigurations. The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. The act of switching roles should be a well-planned activity. Always try to perform a complete failover first unless redo apply has stopped at the failover target due to an ORA-752 or ORA-600 [3020] error. Credentials Required for Access to Broker Configurations. In this example, the original primary data is called PRIM and the original standby database is called STAN. 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). As described in theFlashback Database section, Flashback Database takes place in two stages: a restore stage and a media recovery stage. Syntax for Mandatory Configuration Declaration. In Maximum Availability mode, FSFO guarantees that no transaction that has received a commit acknowledgment will be lost during a failover. db_domain . Another consequence of immediate failover is that all other databases in the configuration are disabled and must be reinstated or re-created before they can serve as standby databases for the new primary database. The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. The observer immediately initiates a fast-start failover, as long as the failover target database is in a valid fast-start failover state ("observed" and either "synchronized" or "within lag") to accept a failover. This article - the seventh in this ongoing . performance protection mode with fast-start failover. For Active Oracle Data Guard, it will fail to open up a connection unless its in read-only mode. specified, the file is stored in an appropriate directory under the broker's However, you do have the option of specifying a name and location for the observer configuration file. See Choosing a Target Standby Database for helpful advice. [PATCH V3 0/6] ASoC: codecs: Add Awinic AW883XX audio amplifier driver FSFO configurations in Maximum Performance mode may limit potential data loss by specifying the maximum allowable age of transactions that are lost during a failover. Oracle Data Guard is a solution provider to businesses by offering data protection and its disaster recovery along with its high availability. Theoretically, this method can be used when a data guard failover occurred between the primary and standby database, but not a switchover. Commit latency is not affected by redo transfer, but committed transactions whose redo has not been received by the standby will be lost during failover. The selected standby database that will be the fast-start failover target must receive redo directly from the primary 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. It is then configured to be active in the PHYSICAL_STANDBY role on the physical standby database SOUTH. It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. For example, perform full level 0 backups weekly and incremental level 1 backups daily. 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. ObserverPingRetry properties before The observer automatically starts the reinstatement process. Broker maintains these parameters by issuing ALTER SYSTEM commands as appropriate during role transitions, database startup/shutdown, and other events. 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. 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. Getting the Oracle Net configuration right is one of the key factors in a successful FSFO deployment. To achieve 8.2 Private Cloud Appliance and . In addition, some standby databases may be disabled by the broker during the failover if the broker detects that they have applied redo beyond where the new primary database had applied. . Use the 'show fast_start failover' command to see which user configurable FSFO failover conditions are in effect. Commands For Managing Observers on Multiple Configurations. Broker stores it configuration information in a mirrored set of files outside the database. The primary database can be reinstated if it had flashback database enabled. 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. Create a trigger on this event to perform actions specific to your environment after a switchover or failover, such as updating the name resolution service to point to the new primary. For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. The original primary database can now be configured as a standby. This will signal the observer to initiate failover after the FSFO threshold timeout has been reached (default is 30 seconds). ORACLE instance shut down. If the status is SUCCESS, you're ready to start testing role transitions. In this mode, the FastStartFailoverLagLimit configuration property is set to zero. Make some new changes and verify that they are preserved after failover. If you already have an FRA, you may need to increase its size in order to accommodate the Flashback Database files. When querying the V$DATABASE view, pay special attention to the following: The FS_FAILOVER_STATUS column, which can contain the values described in Table 6-2. Click Disable in the Fast-Start Failover wizard. 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. 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. See the START OBSERVER 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. You can also specify a list of ORA- errors that will initiate FSFO failover. Use the VALIDATE STATIC CONNECT IDENTIFIER command to ensure the static services have been configured correctly. Such preparation includes: Ensuring that standby redo log files are configured on the primary database. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. Reconnect within the time specified by the FastStartFailoverThreshold property. Issue the following SRVCTL commands: Now the correct services are running on the correct databases. You can use the SHOW CONFIGURATION WHEN PRIMARY IS command to show the redo transport configuration (based on each member's setting of the RedoRoutes property) that would be in effect if the specified database were the primary database. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. It is also supported for fast-start failover to physical standbys in maximum availability data protection mode. observers are registered, a directory named You can disable fast-start failover if necessary, by using the FORCE option. For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. Client-side broker 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. In this mode, no actual changes are made to your Broker configuration. It is very much useful, when the organization has multiple standby sites. STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. db1_a: Alias to connect to the dynamic Data Guard service on database "a", db1_b: Alias to connect to the dynamic Data Guard service on database "b", db1_a_static: Alias to connect to the static Data Guard service on database "a", db1_b_static: Alias to connect to the static Data Guard service on database "b". Broker Configuration Has Multiple Registered Observers. services. The reinstated database acts as the fast-start failover target for the new primary database, making a subsequent fast-start failover possible. This property also affects whether the broker skips viability checks of bystander standby databases when a fast-start failover occurs. Thus, the validity of the values of these properties is not verified until after the switchover. pre-callout configuration script and post-callout configuration script. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. Read-Only Standby and Active Data Guard Switches roles between the primary and standby databases. If the target is a snapshot standby database, the broker first converts the database to a physical standby database. We could not find a match for your search. 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. SQL> Select Database_role from v$Database; Hi, I am working in IT industry with having more than 10 year of experience, worked as an Oracle DBA with a Company and handling different databases like Oracle, SQL Server , DB2 etc select name,open_mode,database_role from v$database; Note: Which three are prerequisites for enabling fast-start failover? See Directing a Fast-Start Failover From an Application). Check the spelling of your keyword search. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. Only the master observer can coordinate fast-start failover with Data Guard broker. In 10g, a single wallet can be used for multiple observers, but they must all use the same SYS password.
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