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In the event of a The reduced need for manual intervention can increase availability without increasing management costs. present, you must start the observer manually using the following No instances are shutdown when doing a failover, if the target standby database is either a physical or logical standby. In Oracle RAC configurations, the Inaccessible Logfile and Stuck Archiver health conditions may only be applicable to a single instance. What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? 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. LGWR is unable to write to any member of the log group because on an I/O error. Make sure that your OS environment on the standby is setup. The My Oracle Support note 1625597.1 at http://support.oracle.com for information about compatibility requirements between the observer and DGMGRL, Starting Multiple Observers on a Data Guard Broker Configuration. For example: Using DGMGRL, you can do this by examining the output of the SHOW CONFIGURATION LAG. DGMGRL to manage multiple observers on multiple configurations. created under this directory by DGMGRL will also have the same permissions. Observer uses the value of the DGConnectIdentifier property to connect to and monitor the primary and target standby databases. 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. FastStartFailoverLagLimit property. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. The services include switchover, switchback and 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. The minimum value of ObserverPingInterval is 100 If you want the broker to skip this viability check of bystander standby databases during a complete failover, thus decreasing the overall failover time, set the BystandersFollowRoleChange configuration property to NONE. Application Continuity is supported for Oracle Data Guard switchovers to physical standby databases. 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. Configure one or more active standby databases Minimize downtime for upgrades The selected standby database that will be the fast-start failover target must receive redo directly from the primary database. However, you can change the name or the location of the file if you start the observer using the DGMGRL START OBSERVER command and include the FILE IS qualifier. The default name of the callout configuration file is What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. command on the observer computer: The observer is a continuously executing process that is upheld. file (fsfo.dat). If failover is not possible for some reason, then the master observer will continue checking whether the standby database is ready to fail over. Start the observer by running dgmgrl and logging in using SYS credentials. See the Cloud Control online help for more information. Your email address will not be published. Automatic failover is optional and can be enabled or disabled on your Autonomous Container Databases with Autonomous Data Guard. The minimum STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. Note: Data Guard requires dedicated server connections for proper operation. When the primary database and the target standby database regain network connectivity, the broker will disable fast-start failover for the entire broker configuration. This allows for redundancy in your Data Guard observer setup as well. 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. Initiate the switchover on the primary database PRIM: See "Database Service Configuration Requirements" for additional information about how the broker interacts with Oracle Restart. After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. In maximum performance mode, the ability to automatically failover is restored The broker reinstates bystander standby databases that were disabled during a failover as standby databases to the new primary database. 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 case, the primary database stalls and prevents any further transactions from Issue the following SRVCTL commands: Now the correct services are running on the correct databases. The steps in this section describe the tasks involved to perform a manual failover. The syntax for the configuration declaration is: The definition for each broker configuration is: The configuration-name can be different from the name defined in the metadata of the Data Guard Broker configuration. Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. By default, the observer creates this file in the current working directory when it is started and names the file fsfo.dat. ObserverConfigFile is a DGMGRL session runtime property. time, if all the sessions that are connected though the active services The drain_timeout is specified in the SRVCTL It will also alert you to databases that have had Flashback Database disabled at some point after FSFO was enabled. command START OBSERVER IN BACKGROUND. It must appear as the first part of an observer configuration file. 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. For any work, queries and help. 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. These clients can be configured for Fast Connection Failover (FCF) to automatically connect to a new primary database after a failover. ), The RedoRoutes property on a far sync instance if it is being used to receive redo from the primary database and ship redo to the target standby database, The standby database that is the target of fast-start failover, A far sync instance if it is being used to receive redo from the primary database and ship redo to the target standby database, Unless the conditions listed in Performing Manual Role Changes When Fast-Start Failover Is Enabled have been met, To a standby database that is not configured as the fast-start failover target. Perform a switchover to a standby database that is not configured as the fast-start failover target, Perform a switchover to the target standby database in a configuration operating in maximum availability mode, unless the standby database is synchronized with the primary database, Perform a switchover to the target standby database in a configuration operating in maximum performance mode, unless the standby database is within the lag limit of the primary database. The minimum detection time is 6 seconds, which is the default 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. This exercises the configuration, but triggers failover differently than losing contact with the primary. If this You want to prevent fast-start failover from occurring because the primary database will resume service soon. restart the new physical standby database. first recording that a fast-start failover cannot happen. The observe-only mode for fast-start failover enables you to test how fast-start failover will work in your environment. fsfocallout.ora. There is no impact on your current configuration or on applications. The failed primary database requires reinstatement as a new standby database to the new primary. there is a lost network connection, be aware that the observer may attempt a Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. The ObserverPingInterval Displays only on a logical standby database that has not yet completed loading a copy of the primary database's data dictionary. Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). Create a pre-callout script, or a post-callout script, or both. property. created when the START OBSERVER command is issued. Then, on the Failover Confirmation page, click Yes to invoke the default Complete failover option. See Enabling Fast-Start Failover for more information. maximum availability and maximum performance modes, to avoid a We will create 4 SRLs starting with group# 11. Before enabling fast-start failover, use one of the following techniques If the primary database has multiple standby databases, then you can specify multiple fast-start failover targets, using the FastStartFailoverTarget property. Add the SRLs. Default value is 100 If the configuration is not failable, the DBMS_DG.INITIATE_FS_FAILOVER function returns an ORA error number (it does not signal an exception) informing the caller that a fast-start failover could not be performed. If reinstatement of a database fails, its status changes to ORA-16795: the standby database needs to be re-created. The observer is the third party in an otherwise typical primary/standby Data Guard configuration. Make sure the last redo data transmitted from the Primary database was applied on the standby database. It is instructive to watch the alert logs on both databases as well as the observer log after aborting the primary to gain insight into what happens during FSFO failover. Oracle Database 11g FSFO adds support for Maximum Performance mode (async redo transfer), providing the flexibility to trade durability for performance. 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. The default name for It has two parts in the following order: Configuration declaration this section is mandatory. The following conditions apply when multiple observers are registered for one configuration: When fast-start failover is enabled, one of the observers is the master observer. 2. from another DGMGRL session. If the primary or target standby databases lose connections to all backup observers, then the broker does not try to nominate a backup observer as the new master observer, and the broker reports that the configuration is not observed. 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. The FS_FAILOVER_STATUS column in the V$DATABASE view for the target standby database displays a reason why fast-start failover cannot occur. The role change is directed to the same standby database that was specified for the FastStartFailoverTarget database property on the primary database. primary, only the observers specified in the property can be use in the SET fast-start failover through Cloud Control. operation can be automated using callout scripts. Use the SHOW CONFIGURATION BystandersFollowRoleChange command to see the value of this property. The following is an example of querying the V$FS_FAILOVER_STATS view: Disabling fast-start failover prevents the observer from initiating a failover to the target standby database. Facebook:https://www.facebook.com/HariPrasathdba In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. Fast-Start Failover allows Data Guard to automatically failover to a previously chosen standby database without requiring manual intervention to invoke the failover. In the following example, a service named sales is configured to be active in the PHYSICAL_STANDBY role on the primary database NORTH. An observer process is integrated in the DGMGRL client-side component of the broker and typically runs on a different computer from the primary or standby databases and from the computer where you manage the broker configuration. The remaining observers are called backup observers. You can use Cloud Control or DGMGRL, to perform either a complete (recommended) or an immediate failover. For example, if the old standby was a physical or snapshot standby, then the old primary must be re-created as a physical standby. It behaves similarly to START OBSERVING and STOP OBSERVING to operate on all the configurations defined in the observer configuration file. The ObserverOverride and ObserverReconnect properties allow you additional control over the connection to the primary. If Flashback Database history is insufficient, the observer will not be able to reinstate and you will have to manually reinstate from backup or by primary duplication. DNS CNAME) that always resolves to the primary. command for more information about starting the If the observer finds that the database is no longer the primary, it will attempt to reinstate it as the failover target standby. You must determine which available standby databases should be targets for failover. name of the observer log file is See the Oracle Reference and Data Guard Administrator guides for your release for details. If the primary database can be mounted, it may be possible to flush any unsent redo data from the primary database to the target standby database using the ALTER SYSTEM FLUSH REDO SQL statement. If Flashback Database fails, automatic reinstatement stops and you will have to perform a manual SCN-based recovery to the standby_became_primary_scn and complete the reinstatement. the SYSDG or SYSDBA privilege. Use the callout configuration file and script The FastStartFailoverLagLimit configuration property is only used by the broker when enabling fast-start failover for configurations operating in maximum performance mode. This table describes the optional database properties that you can set. To protect the files, it's good practice to store them in separate filesystems. Use broker configuration properties to set the time taken to detect a After Fast-Start Failover: The fast-start failover has completed and the target standby database is running in the primary database role. If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. must create a .suc and .err file in the In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). If the target standby database is ready for failover, then the master observer immediately directs the target standby database to fail over to the primary database role. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . Any database that was disabled while multiple role changes were performed cannot be reinstated. 8.2 Private Cloud Appliance and . This is normal. To prevent automatic reinstatement of the former primary database in these cases, set this configuration property to FALSE. There can be up to four When restarting the databases, you may restart them in any order. 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. FastStartFailoverAutoReinstate is set to FALSE, Another failover or switchover occurred after the fast-start failover completed but before the former primary database restarted, The master observer cannot connect to the former primary database, The former primary database cannot connect to the new primary database, The former primary database and the new primary database are not configured in the same fast-start failover environment, The former primary database was disabled because of a manual failover when fast-start failover was disabled. directory by this environment variable does not exist, or the $DG_ADMIN You can upgrade the protection mode later, if necessary, as described in Setting the Protection Mode for Your Configuration. The following is an example of setting the LogXptMode property: Alternatively, use the RedoRoutes property to set the redo transport mode for the target standby and database that is currently in the primary role. For example: The default value for the FastStartFailoverThreshold property is 30 seconds and the lowest possible value is 6 seconds. They can all be done at the same time in a single bounce. If there are no registered observers when fast-start failover is enabled, then the first observer started is designated as the master observer, and all others started later are backup observers. 1. In this case, Flashback Database cannot be used to reinstate databases. This can be avoided by first disabling fast-start failover with the FORCE option on the target standby. To see Manual Switch Over Manual SwitchOver in Oracle To see Manual Fail Over Manual Failover in Data Guard With Oracle Data Guard [] files to automate tasks that must be performed before and after a fast-start failover If fast-start failover is enabled you can still perform a switchover or a manual failover as long as certain conditions are met. North_Sales is in the primary role. In such cases, the failed primary database is reinstated as a physical standby database. may allow the primary database to continue redo generation after This specifies how often the observer establishes a new connection to the primary database. connectivity with target standby. Commands For Managing Observers on Multiple Configurations. The name of the callout configuration file is fsfocallout.ora. To proceed, you must first disable fast-start failover using the FORCE option, and then perform a manual failover. See Directing a Fast-Start Failover From an Application). You can switch back to the original primary and then either retry the switchover to the original target standby, or choose another standby in the configuration to switch over to. The example below takes advantage of the 11g RMAN Active Database Duplication feature. This nomination is noted in the observer log file and in the broker log file (drc*.log). Stores the observer runtime data file and observer configuration file in See Manual Failover for information about manual failover. In this case fast-start failover cannot occur because the databases are not ready to failover. Only the observer can initiate FSFO failover. A fast-start failover to the target standby database fails. The rest of this section provides examples of using DGMGRL SHOW commands to display fast-start failover information and includes sections describing the following views: The DGMGRL SHOW FAST-START FAILOVER command displays all the fast-start failover related information. Make sure that xdpyinfo exist under PATH variable. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL.