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. Cloud Control will start the observer. Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. time specified in the WAIT option. This is true regardless of the settings for the FastStartFailoverPmyShutdown and FastStartFailoverAutoReinstate configuration properties. If it's not, DGB will not allow the failover to continue until the DBA has manually resolved any discrepancies. There are two types of failover operations: Graceful or "no-data-loss" failover and Forced or "minimal-data-loss" failover. callout configuration scripts fsfo_precallout and See Performing Manual Role Changes When Fast-Start Failover Is Enabled for more information. The foundation of FSFO is Data Guard - a primary and at least one standby. Use the Cloud Control Fast-Start Failover wizard or the DGMGRL ENABLE FAST_START FAILOVER command to enable fast-start failover. 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. Administration at the target standby site should be as comprehensive as that at the primary site because the standby database may assume the primary role without prior notice. If failover occurs to a logical standby database, all physical and snapshot standby databases will be disabled by the broker. The following table summarizes which standby types are supported in which protection modes when fast-start failover is enabled. Any standby database that was disabled by the broker must be reinstated or re-created, as described in Reenabling Disabled Databases After a Role Change, before it can be a standby database for the new primary database. The value specified for either of these properties should allow the master observer to connect to any instance of an Oracle RAC database. 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. For Maximum Availability environments, change this to synchronous. A number of prerequisites must be met on the primary in order to use Fast-Start Failover. The configuration must be operating in either maximum availability mode or maximum performance mode in order to be able to switch over to a logical standby database. Valid values are >= 10. This property allows you to specify a priority ordered This can be compared to performing an RMAN restore of the datafiles from a backup taken prior to the specified SCN, but is much faster. Select name,open_mode,database_role from v$database; Step:2 Cancel the MRP process You can disable fast-start failover if necessary, by using the FORCE option. When the standby becomes available again, the primary and standby re-synchronize and resume synchronous redo transfer. By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. FB Group:https://www.facebook.com/groups/894402327369506/ See Sources of Diagnostic Information for details about the broker's drc* log files. It provides a way to quickly restore a database to a previous point in time or SCN using on-disk data structures called flashback logs. Now let's test switchover in the other direction. By default, a fast-start failover is done when both the observer and the standby cannot reach the primary after the configured time threshold (FastStartFailoverThreshold) has passed. (Yes, bystanders need Flashback Database too). 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. 1. Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). If the former primary database cannot be reinstated automatically, you can manually reinstate it using either the DGMGRL REINSTATE command or Cloud Control. Use Broker's "show configuration" command to determine FSFO status and the "show database statusreport" command to drill down for details if Broker reports a problem. Add the SRLs. This allows Data Guard to remain functional during maintenance periods when the application listeners are down. 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. Only two databases, the primary and the failover target, can be in the FSFO configuration at any given time. This 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. One is the master If the Cloud Control agent is installed on the observer These are the guidelines for choosing a target standby database. In this case, the primary database stalls and prevents any further transactions from Broker will set the primary to use asynchronous log transport by default. SQL> Select Database_role from v$Database; The required attributes vary depending on your configuration (including whether your environment is Oracle RAC-based or single-instance). What is true about Data Guard setup with fast-start failover? 8.2 Private Cloud Appliance and . The platform provides comprehensive services such as maintaining and monitoring databases to help the oracle databases in surviving during data corruption. If it reconnects to the primary database before the standby agrees to fail over, then the master observer will stop attempting to initiate a fast-start failover. 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. These facilities allow applications written to take advantage of them to receive asynchronous notification of database events, including role transitions. data (in seconds) specified by the Configure Data Guard Broker to manage and monitor the Data Guard configuration. This is Note: if the observer loses contact with the primary, but the standby does not, the observer can determine that the primary is still up via the standby. By choosing the standby database with the least amount of unapplied redo, you can minimize the overall time it takes to complete the switchover operation. In short, the failover is the deformation of the production (primary) database and activating standby database as the primary. 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. A database in the primary role will not open until it has verified with the observer that it is still the primary. Don't initiate failover unless at least 30 minutes of history is available. 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 To enable fast-start failover with DGMGRL, issue the ENABLE FAST_START FAILOVER command while connected to any database in the broker configuration, including on the observer computer. All Data Guard environments require the use of a password file in order to allow the databases to connect to each other. After a failover, a bystander will not automatically become the new failover target. Indexing is a mechanism by which the underlying data is mapped for faster retrieval. switch does not happen until the next time the primary contacts the target standby, The ObserverPingInterval See Troubleshooting Problems During a Switchover Operation for more information. How to Re-create and Reenable a Disabled Database. A complete failover also attempts to avoid disabling any standby databases that were not the target of the failover, so that they may continue serving as standby databases to the new primary database. This page will not allow you to alter the protection mode. OBSERVE-ONLY: Fast-start failover is enabled in observe-only mode. miliseconds. Were sorry. Reinstatement is supported only after failover in a broker configuration. If the configuration contains physical, snapshot, and logical standby databases, consider choosing a physical standby database as the target standby database. 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. The broker controls the rest of the switchover. is guaranteed to lose no more than the amount of You can, however, perform a manual failover to a snapshot standby. 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. The standby database must be re-created or reinstated before it can serve as a standby for the new primary database. 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. These are the actions the broker performs after you start a switchover. 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. If reinstatement of a database fails, its status changes to ORA-16795: the standby database needs to be re-created. The "Configuring Authentication" chapter of the Oracle Database Security Guide provides detailed instructions for creating a wallet. name of the observer log file is You can specify STOP OBSERVER ALL to stop all observers registered in a broker configuration. 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. Create a wallet and set the default username and password to the database's SYSDBA credentials (usually SYS). More specifically, we can have an asynchronous second read-only Managed instance in the same or in a different region. When using DGMGRL, you need to issue the SWITCHOVER command, specifying the name of the standby database that you want to change into the primary role. It will return PRIMARY, isolated. The real test of the configuration is a successful role transition in both directions with both switchover and FSFO failover. Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. Errors occurring for any other configuration members will not impede the switchover. After a failover, the broker publishes Fast Application Notification (FAN) events. If this 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. 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). been enabled on the database prior to the failover and there must be sufficient observer computer is returned to you so that you can continue to It is actually a low-footprint OCI client built into the DGMGRL CLI (Data Guard Broker Command Line Interface) and, like any other client, may be run on a different hardware platform than the database servers. present, you must start the observer manually using the following Make sure that xdpyinfo exist under PATH variable. After the broker receives the STOP OBSERVER request, the request is passed to the observer the next time the observer contacts the broker, and the observer then stops itself. A failover to a physical standby database is preferable because 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. Busca trabajos relacionados con New sql server failover cluster installation greyed out o contrata en el mercado de freelancing ms grande del mundo con ms de 22m de trabajos. 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. Read-Only Standby and Active Data Guard Credentials Required for Access to Broker Configurations. SQL> Select Database_role from v$Database; Fast-start failover quickly and reliably fails over the target standby database to the primary database role, without requiring you to perform any manual steps to invoke the failover. This list describes restrictions when fast-start failover is enabled. Broker Configuration Has Only One Registered Observer. https://www.facebook.com/dbahariprasath/? Switchover and Manual Failover for more information about switchovers and manual failovers, respectively. After you click the Reinstate button, Cloud Control begins reinstating the database. However, the event notifying a failover is only published for database services that have been configured to be active while the database is in the primary role on the new primary database. The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. Starting the Observer Using Cloud Control. ConfigurationSimpleName. The ObserverOverride configuration property, when set to TRUE, allows an automatic failover to occur when the observer has lost connectivity to the primary, even if the standby has a healthy connection to the primary. The following is an example of querying the V$FS_FAILOVER_STATS view: Disabling fast-start failover prevents the observer from initiating a failover to the target standby database. In order to fully automate switchover, Broker needs SYSDBA credentials in order to restart one or both databases. The DB_ROLE_CHANGE event will fire whenever a database is opened for the first time after a role transition. ORACLE instance shut down. When the observer loses its connection to the primary database for a period of time greater than that specified by the FastStartFailoverThreshold property, it attempts a failover to the standby database. have received all the redo data the primary has generated in order for automatic failover to database is in the primary role. This guide uses the naming convention of appending an underscore followed by a letter to the db_name to create the db_unique_name.
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