Once the observer has initiated a fast-start failover, the primary database shuts down automatically. Steps to Create a Physical Standby Databa se 3 -3 Preparing the Primary Database 3 -4 FORCE LOGGING . Once you set these properties, their values persist through role changes during switchover and failover. CONNECT command. 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. You can also switch the master observer hosts for a group of configurations to one specific host. This brings up the General Properties page that provides a Reinstate button. Verify Before Switch-over: This is Flashback Database records the before-image of changed blocks. Oracle Data Guard with Fast-Start Failover (FSFO) can provide additional resiliency by setting up the broker on a separate machine. When fast-start failover is disabled, no observer is called the master observer; all observers have the same functionality. multi-tenant environments Know the database downgrade steps in case the upgraded database isn't compatible with the environment Discover the features and benefits to the organization when it moves from the old database . Then set the configuration protection mode to maximum availability. This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. failover configuration file, this script is run. 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. The broker first converts the original primary database to run in the standby role. FastStartFailoverLagLimit configuration property is set to zero) or ERROR: Unable to verify the graphical display setup. It is important that all SRVCTL add service options be identical on all the databases so that the services behave the same way before and after a role change. For systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. The subcommands for this verb include start, stop, setMaster, show, and delete_alternate_observer. When enabled, re-create the standby database. To stop it, you can do either of the following: Choose the Stop Observer option on the first page of the fast-start failover wizard and click Continue at the bottom of the page. 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. The real test of the configuration is a successful role transition in both directions with both switchover and FSFO failover. If the standby database is not enabled for management by the broker, then the failover cannot occur. You The minimum value of ObserverPingInterval is 100 During an immediate failover, the broker performs the failover steps described in How the Broker Performs an Immediate Failover Operation. To verify the observer is started and the configuration is ready for These are the actions the broker performs after you start a switchover. switch does not happen until the next time the primary contacts the target standby, To maximize the benefits of FSFO, the observer should run on a different host than the primary and standby databases. You can also query the V$FS_FAILOVER_STATS view to display statistics about fast-start failover occurring on the system. In a Data Guard environment primary database is open in read write mode and the standby database in read only mode for reporting purpose. The failed primary database requires reinstatement as a new standby database to the new primary. The example uses the FROM ACTIVE DATABASE clause introduced in 11g that allows RMAN to create a standby database by copying the primary across the network without the need to store the backup files on disk or tape. These Standby databases that are disabled during switchover, manual failover, or fast-start failover will not be automatically reinstated. Verifies that the target standby database is enabled. Now test FSFO failover back to the original primary. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL. See Troubleshooting Problems During a Switchover Operation for more information. The simplest way to do this is to abort the primary. lower detection times for primary database failures, you must 11.2 rac servicefailover 2020-01-28 ORACLE ORACLE RAC/ASM RAC112. Immediate Failovers in Configurations Using Cascaded Standbys. It comes with a GUI and command line interface. an alias of the broker configuration name. These are the actions the broker performs after you start a complete failover. 1. If the observer is unable to regain a connection to the primary database within the specified time, and the target standby database is ready for fast-start failover, then fast-start failover ensues. Issue the DISABLE FAST_START FAILOVER command or the DISABLE FAST_START FAILOVER FORCE command. observer_hostname.log. standby database, host, or network failure, etc.). (as it might in maximum availability and maximum performance modes). Therefore, the primary database can continue processing transactions, even if the target standby database fails. Broker can be configured to initiate failover on any of the following conditions. files include the observer configuration file (observer.ora), observer log automatic failover feature in configurations set up for zero data loss protection at any 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. Unlike the primary / standby interconnect, where bandwidth and latency are determining performance factors, the observer requires very little network bandwidth and is not overly latency sensitive, allowing the it to be placed practically anywhere a reliable connection is available. JAVA applications can use FAN programmatically by using the JDBC FAN application programming interface to subscribe to FAN events and to execute event handling actions upon the receipt of an event. These requirements are supplemental to those described in the documents previously referenced and in the following client-specific guides: Oracle Data Provider for .NET Developer's Guide for Microsoft Windows. DGMGRL> show configuration Configuration - CDB01_fraad1_CDB01_fraad3 Protection Mode: MaxAvailability Members: CDB01_fraad1 - Primary database CDB01_fraad3 - (*) Physical standby database Flashback Database is a continuous data protection (CDP) solution integrated with the Oracle Database. 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. For the RMAN duplicate active database method, the init.ora file (initdb1.ora in the example) requires only one parameter: db_name (it doesn't even have to be the real name of the database - any name will do). fast-start failover to the target standby database if conditions warrant a failover. 1 second. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . VALIDATE STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. 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. It's secondary job is to automatically reinstate a failed primary as a standby if that feature is enabled (the default). the ObserverPingRetry and ObserverPingInterval properties to achieve Then, on the Fast-Start Failover Change Mode page, click Enabled. Disabling Fast-Start Failover Using Cloud Control. When you run commands that need access to the observer For example: Ordinarily the observer connects once to the primary and does not attempt to reconnect unless the connection has failed. 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. If you intend to switch back to the original primary database relatively soon, you may allow the physical and snapshot standbys to remain disabled. PRIM> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN; REINSTATE REQUIRED is present only after fast-start failover has occurred and shows on both the new primary database and the database undergoing reinstatement. Start the Data Guard listener on both "a" and "b" hosts. The database cannot provide fast-start failover status information. For instance, you could log into the system running observer1 to stop observer2. 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. Note that if failover was performed on a snapshot standby database, the old primary must be either reinstated or re-created as a physical standby database. Apply services on all other bystander standby databases automatically begin applying redo data received from the new primary database. once the target standby database's redo applied point is no longer lagging behind the primary A high lag limit may lead to more data loss but may lessen the performance impact of the primary database. Initiate the switchover on the primary database PRIM: SQL> select name,open_mode,database_role from v$database; NAME OPEN_MODE DATABASE_ROLE --------- -------------------- ---------------- MYTEST MOUNTED PHYSICAL STANDBY Step 2: Apply the following command to finish database recovery. directory has the same permissions as its parent directory. The guide attempts to be operating system agnostic; however, some examples may contain platform specific elements such as path and file naming conventions. A far-sync instance cannot be used in maximum protection mode. After a role change, the naming service can be updated with the new primary's address. The FORCE option disables fast-start failover on the database to which you are connected even when errors occur. This database property is used to specify how the observer should connect to and monitor the primary and standby database. See Oracle Data Guard Concepts and Administration for information about tuning the log apply rate for a physical standby database. Verify there are no active users connected to the databases. To stop the observer when fast-start failover is disabled, the primary database must be running. Configure Data Guard Broker to manage and monitor the Data Guard configuration. START OBSERVING [cfg_group_name] starts a new observer for each broker configuration in the specified group. 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. time specified in the WAIT option. Written by authors well-known for their talent with RAC, Pro Oracle Database 11g RAC on Linux . What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? This section describes how to stay on top of your FSFO environments. 3. Table 6-3 FS_FAILOVER_OBSERVER_PRESENT Column of the V$DATABASE View, The master observer is currently connected to the local database, The master observer is not connected to the local database. Data Guard Broker - Controls the creation and monitoring of Data Guard. To achieve SHOW ObserverConfigFile used to check the runtime property ObserverConfigFile. 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. North_Sales is in the primary role. ObserverConfigFile is a DGMGRL session runtime property. A switchover is a role reversal between the primary database and one of its standby databases. redo generation on the primary database will be stalled. 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. Dataguard Switchover Using DGMGRL A switchover is a role reversal between the primary database and one of its standby databases. 5. 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). operation: Example 6-1 Fast-start Failover Configuration Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring FAN, FCF, and ONS on an Oracle Real Application Clusters (Oracle RAC) database. configuration file exists. The same process should work for RAC environment as my colleague has . environment variable must have exclusive permissions wherein it can be accessed only Subdirectories within The general approach seems to be CDB level failover to standby , so the failover takes place at CDB to CDB , in an event where a single PDB is experiencing an issue , we will have to failover the whole instance ..this will impact all PDB's on the CDB. the location of the observer log file, and the location of the observer runtime data On Linux/Unix, the directory specified by the DG_ADMIN environment Media Recovery - Once the restore is complete, recovery proceeds as a typical media recovery, applying redo from archived and online redologs and rolling back uncommitted changes with undo. 8.2 Private Cloud Appliance and . The information shown by this command is the same as that shown by a SHOW OBSERVER command on each individual configuration. This property also affects whether the broker skips viability checks of bystander standby databases when a fast-start failover occurs. Facebook:https://www.facebook.com/HariPrasathdba broker configuration, you must connect through another DGMGRL client This walkthrough uses Maximum Availability mode to achieve "zero data loss". In Oracle RAC configurations, the Inaccessible Logfile and Stuck Archiver health conditions may only be applicable to a single instance. The remaining Data Guard-related parameters will be set by Broker later in the walkthrough. STANDBY>ALTER DATABASE OPEN; This property specifies the amount of data, in seconds, that the target standby database can lag behind the primary database in terms of redo applied. The existence of a .suc file, 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. 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. If you re-create the old primary database, it must be created as the standby type of the old standby database. 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. Relationship Between Primary, Target Standby, and Observer During Fast-start Failover. RAM). In this example, the original primary data is called PRIM and the original standby database is called STAN. The service can be started on the physical standby only after the redo generated by starting the service has been applied. Updates the broker configuration file to record the change in roles. Displays on the primary database after loss of connectivity to the target standby database and the change to the UNSYNCHRONIZED state (maximum availability mode) or to the TARGET OVER LAG LIMIT state (maximum performance mode) cannot be confirmed by either the target standby database or the observer. 12c upgrade, The below commands will help to bring up standby as primary, https://www.linkedin.com/in/hari-prasath-aa65bb19/, https://www.facebook.com/groups/894402327369506/. Slightly less critical than making sure you've got a good primary is making sure the failed primary can be automatically reinstated. Add the SRLs. The reduced need for manual intervention can increase availability without increasing management costs. The master observer uses the value specified by either the DGConnectIdentifier or ObserverConnectIdentifier database properties to connect to the primary and fast-start failover target standby databases. For example: In the following example, assume the network between the primary database and the observer has failed. This section describes how to configure and verify each prerequisite. The time interval starts when the observer first loses its connection to the primary database. 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. 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. Client-side broker The price for this guarantee is increased commit latency ( log file sync waits). Staff support, hardware and software, security (both software and site), network connections, and bandwidth should be equivalent at both sites. It uses these databases as a copy of the . Es gratis registrarse y presentar tus propuestas laborales. A simple example for *nix is provided below that will work with both releases. 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. 3. 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. A fast-start failover occurred because a user-configurable condition was detected or was requested by an application by calling the DBMS_DG.INITIATE_FS_FAILOVER function. In 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). observer and the others are backup observers. observer is still in contact with the standby. This file is stored in the 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. 12c Dataguard, In Flashing back a database occurs in two stages: For FSFO environments, set db_flashback_retention_target = 60 or higher to provide sufficient Flashback Database history for automatic standby reinstatement. Before beginning a failover, first determine that there is no possibility of recovering the primary database in a timely manner, and ensure that the primary database is shut down. 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. Provides an automatic failover environment that When a serious condition uniquely known to an application is detected, the application can call the DBMS_DG.INITIATE_FS_FAILOVER function to initiate an immediate fast-start failover. During a complete failover, the broker performs the failover steps described in How the Broker Performs a Complete Failover Operation. To switchover to a standby that is not the current failover target: John Smiley [jrsmiley@gmail.com] is a persistent storage architect for a major online retailer. Enabling fast-start failover does not trigger a failover. Startup can fail with "ORA-16647: could not start more than one observer" even when no observer is actually running if the previous observer process terminated without deregistering itself and the new observer isn't using the previous fsfo.dat file. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. In maximum protection mode, set the LogXptMode database property to SYNC (note that in maximum protection mode, a far sync instance cannot be used to ship redo to a standby). 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".
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