Please contact us at contactus@smarttechways.com. When restarting the databases, you may restart them in any order. When using Maximum Availability mode, consider lowering this to reduce the time commits block when the standby becomes unavailable. If the DG_ADMIN environment variable is not defined, or the To get started, all you'll need is Oracle Database Enterprise Edition Release 10.2 or later, a database, and three hosts: two for the databases and a small host for the FSFO observer. After a failover, the broker publishes Fast Application Notification (FAN) events. By default, the broker always determines whether bystander standby databases will be viable standby databases for the new primary when performing a complete failover. 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 . redo generation on the primary database will be stalled. The targets are referred to as candidate targets. Open another prompt and connect to SQLPLUS: Tailing the alert logs on the primary and standby is a good way to watch Broker in action and get familiar with how it performs various tasks. As a result, there is no guarantee that the observer will not perform a fast-start failover to the target standby database if the observer determines that conditions warrant a failover. 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. These conditions are described in the following table: Dictionary corruption of a critical database. The FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. If failover occurs to a logical standby database, all physical and snapshot standby databases will be disabled by the broker. The walkthrough begins with a single database that will become the primary of a Data Guard configuration. 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. Just be sure to include a Flashback Database history check in the script to provide an option to abort if a failover would require a manual reinstate. lower detection times for primary database failures. cannot use a different name for this file. (Note that the target standby cannot be a far-sync instance. This is a good time to enable FSFO to make sure that all of the prerequisites have been met. Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs You can also switch the master observer hosts for a group of configurations to one specific host. The observer is perfectly satisfied if all of the redo it needs to meet your durability requirements has been received by the failover target. After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. Immediately after issuing command in step 2, shut down and restart the former primary instance PRIM: For Oracle RAC databases, see Oracle Real Application Clusters Administration and Deployment Guide for more information about configuring database services with the SRVCTL utility. The role change is directed to the same standby database that was specified for the FastStartFailoverTarget database property on the primary database. Oracle Database PL/SQL Packages and Types Reference for more information about the DBMS_DG package. If errors occur during the disable operation, the broker returns an error message and stops the disable operation. New sql server failover cluster installation greyed outtrabajos The following steps all require the database to be in a mounted (not open) state. ObserverConfigFile is a DGMGRL session runtime property. 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. 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. Broker changes database parameters during startup and role transitions via ALTER SYSTEM commands. This section describes how to configure an Oracle Net connect descriptor that meets this requirement. Oracle 11g Physical standby data Guard Failover steps - Data Guard Part Because fast-start failover was not disabled on the target standby database, the observer may still attempt a fast-start failover to the target standby database should conditions warrant a failover. environment variable is set and the specified directory has the We suggest you try the following to help find what youre looking for: This document will guide you through configuringOracle Data GuardFast-Start Failover (FSFO) using a physical standby database. SQL> startup ORACLE instance started. The FastStartFailoverThreshold time interval starts when the observer first detects there might be a failure with the primary database. LGWR is unable to write to any member of the log group because on an I/O error. How To Configure Client Failover For Data Guard Connections - Oracle Fast-start failover can incur data-loss within the time specified by FastStartFailoverlagLimit. 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. The Marketplace image that you use to create the VMs is Oracle:Oracle-Database-Ee:12.1..2:latest. The primary database must be running in order to start the observer. When this property is set to NONE, the broker will disable all bystander standby databases without checking whether they have applied more redo data than the new primary database. The foundation of FSFO is Data Guard - a primary and at least one standby. Database hosts are referred to as "a" and "b" hosts and the databases themselves are referred to as the "a" and "b" databases. The target standby database is enabled and is in the APPLY-ON state. This file contains connect identifiers to both the primary and the target standby databases. 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 previous examples dealt with setting up only one service on a database. ObserverConnectIdentifier allows you to specify different connect identifiers for the observer to use. If you are more concerned about the performance of the primary database than a minimal loss of data, consider enabling fast-start failover when the configuration protection mode is set to maximum performance. You cannot perform a manual failover to the target standby database for the same reason. If fast-start failover is already enabled, the 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. 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. Tags: Data Guard, Oracle. Any broker configuration name that is referred to must exist in the configuration declaration section. 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. FastStartFailoverThreshold for reference information about the FastStartFailoverThreshold property. Syntax for Mandatory Configuration Declaration. Initiate reinstatement by mounting the database. expires. Log into the new primary and verify that the changes made it across. If the former primary database cannot be reinstated automatically, you can manually reinstate it using either the DGMGRL REINSTATE command or Cloud Control. mode when the fast-start failover target is a logical or physical standby database that An immediate failover should only be performed when a complete failover is unsuccessful or in the error cases just noted. The PeopleSoft application servers will react accordingly to FAN events exit. The following sections describe how to perform manual failovers: Reenabling Disabled Databases After a Role Change. How to switch roles in Oracle Data Guard - The Geek Diary Each observer has its own log file. files are stored in subdirectories of the DG_ADMIN directory. times that the observer retries a failed ping before it initiates a broker configuration, you must connect through another DGMGRL client The following sections describe these topics: Prerequisites for Enabling Fast-Start Failover, Viewing Fast-Start Failover Configuration Statistics and Status, Performance Considerations for Fast-Start Failover, Reinstating the Former Primary Database in the Broker Configuration, Shutting Down Databases In a Fast-Start Failover Environment. A switchover to a physical standby database is preferable because all databases in the configuration will be available as standby databases to the new primary database after the switchover operation completes. The service is then configured to be active in the PRIMARY role on the standby database SOUTH, so that it will be active on that database after a role transition. automatic failover feature in configurations set up for zero data loss protection at any The default value is 30 seconds and the lowest possible value is 5 seconds. Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. Opens the new primary database in read/write mode. 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. See the Oracle Reference and Data Guard Administrator guides for your release for details. Then, In this mode, the FastStartFailoverLagLimit configuration property is set to zero. To start an observer as a background process, use the DGMGRL Rather, fast-start failover will be enabled in accordance with the current protection mode. upheld. See the "DISABLE FAST_START FAILOVER" command in Oracle Data Guard Command-Line Interface Reference for more information. Because the broker performs the failover after converting the snapshot standby database to a physical standby database, 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. The guide attempts to be operating system agnostic; however, some examples may contain platform specific elements such as path and file naming conventions. These FAN events can be used in the following ways: Applications can use FAN without programmatic changes if they use one of these Oracle integrated database clients: Oracle Database JDBC, Oracle Database Oracle Call Interface (OCI), Oracle Data Provider for .NET ( ODP.NET), or Universal Connection Pool for Java. Data Guard | Oracle 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 there are many actions that need to take place, put them in a separate script and use the trigger to run the script in an orphan process or thread independent of the database. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . Starts redo transport services to begin transmitting redo data to all bystander standby databases that were not disabled. the service configuration. failure on the primary database. The information in this guide is based on practical experience gained from deploying FSFO in a global corporate production environment. only. Whether or not you need the FORCE option depends mostly on if the primary and target standby database have network connectivity: If the primary and target standby database have network connectivity, and the database to which you are connected has network connectivity with the primary database, the FORCE option has no effect. See the Cloud Control online help for more information. The example uses 10 seconds. For example: Scenario 6: Enabling Fast-Start Failover and Starting the Observer. You can switch over or manual failover to a bystander database. add service command. variable must have read, write, and execute permissions for the directory owner Subdirectories within Note that the new primary database does not need to be restarted. For example, to determine if fast-start failover can occur, the FS_FAILOVER_STATUS column displays either SYNCHRONIZED or TARGET UNDER LAG LIMIT and the FS_FAILOVER_OBSERVER_PRESENT column displays YES for the target standby database. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. An alternative is to enable flashback database on the primary (and the standby if desired) so in the event of a failover, the primary can be flashed back to the time before the failover and quickly converted to a standby database. You can specify STOP OBSERVER ALL to stop all observers registered in a broker configuration. The simplest way to do this is to abort the primary. database is managed by Oracle Clusterware, broker directs Oracle Clusterware to If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. It automatically recovers the maximum amount of redo data for the protection mode the configuration is operating in. configuration named ConfigurationSimpleName. See Setting the Protection Mode for Your Configuration. Standby databases not involved in the switchover (known as bystander standby databases) continue operating in the state they were in before the switchover occurred and will automatically begin applying redo data received from the new primary database. The name of the callout configuration file is fsfocallout.ora. To optimize the log apply rate: Do not configure the DelayMins database property to delay applying archived redo log files to the standby database (see Managing Log Apply Services for more information). Provides an automatic failover environment The column value for V$DATABASE.FS_FAILOVER_STATUS will be SYNCHRONIZED in a configuration operating in maximum availability mode, and it will be TARGET UNDER LAG LIMIT in a configuration operating in maximum performance mode when ready to fast-start failover. What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? file also declares broker configurations and defines configuration Create a wallet and set the default username and password to the database's SYSDBA credentials (usually SYS). Oracle Data Guard provides the ability to create and maintain Standby databases at one or more sites These protect Oracle databases from database and server failures as well as site disasters Failover to one of the alternate sites can be set to happen automatically (fast-start failover) or manually if the primary database is not usable environment that is guaranteed to either lose no data (when the 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. Start the observer by running dgmgrl and logging in using SYS credentials. 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. Figure 6-2 The Observer in the Fast-Start Failover Environment. Observers continuously monitor the fast-start failover environment to ensure the primary database is available (described in When Fast-Start Failover Is Enabled and the Observer Is Running). configuration file The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. Immediate Failovers in Configurations Using Far Sync Instances. See Disabling Fast-Start Failover. status before the crash. 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 systems with multiple RAID controllers, consider creating SRLs such that their IO is balanced across the controllers. Figure 6-2 shows the observer monitoring a fast-start failover configuration. PRIM>SHUTDOWN IMMEDIATE; select name,open_mode,database_role from v$database; Note: These are the guidelines for choosing a target standby database. See the START OBSERVER command for more information. This allows Data Guard to remain functional during maintenance periods when the application listeners are down. Do this prior to every failover test. 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. Then, on the Fast-Start Failover Change Mode page, click Enabled. FAN events are published using Oracle Notification Services (ONS) for all Oracle integrated database clients in Oracle Database 12c and later. See Reenabling Disabled Databases After a Role Change. Perform SWITCH LOGFILE if necessary. Broker can be configured to initiate failover on any of the following conditions. 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). This list contains some recommendations to obtain better performance when using fast-start failover. Among many benefits of using this utility, I highlight that while using it, it will not need manual intervention to recover the databases or eventually a switchover in case the primary database becomes unavailable. In the rare event that a switchover operation fails and you are left with no primary database, retry the switchover command. observer immediately begins monitoring the status and connections to ObserverPingRetry configuration properties. Manual failover to the fast-start failover target can be performed without receiving an acknowledgement from the observer. If you intend to switch back to the original primary database relatively soon, you may allow the physical and snapshot standbys to remain disabled. command is submitted successfully, the command-line prompt on the The default value is 30 seconds. Using Shared Server (MTS) or connection pooling can result in unpredictable behavior. primary, only the observers specified in the property can be use in the SET How to Enable Fast-Start Failover in Oracle Data Guard Such preparation includes: Ensuring that standby redo log files are configured on the primary database. If the WAIT option is included in the The observer host is 'observer.demo.org'. this directory are used to store the files related to the FSFO builds upon a number of other Oracle technologies and features such as Data Guard, Flashback Database, and Data Guard Broker. No two observers on the same Data Guard Broker configuration can have the same name. The Column Value in the following table is consistent across instances in an Oracle Real Applications Clusters (Oracle RAC) environment. Thus, the validity of the values of these properties is not verified until after the switchover. Use the callout configuration file and script Execute the following on primary database NORTH: Execute the following on the physical standby database SOUTH: If the broker now performs a switchover or failover, it automatically starts the SALES service on the correct database, based on the database's role. Even if you have successfully connected to a database server in the broker configuration using the CONNECT command, this command ignores the existing connection and uses the credentials stored in Oracle wallet. Slightly less critical than making sure you've got a good primary is making sure the failed primary can be automatically reinstated. 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. You can manage observers through either the Oracle Data Guard Overview pages in Cloud Control or using DGMGRL commands. 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. milliseconds and that of ObserverRetryCount is 10. This can be avoided by first disabling fast-start failover with the FORCE option on the target standby. 1. Therefore, the target standby never falls behind the primary If the service has been configured to start automatically (-policy AUTOMATIC), then the service will automatically start only after a database role change. standby database is mounted, broker remembers this setting. Now your old standby database is become primary database, it is highly recommended to consider immediate full backup of primary database. How to reinstate the old Primary as a Standby after Failover in #Oracle The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. Displays when the primary and target standby databases are synchronized and the configuration is operating in maximum availability mode. Credentials Required for Access to Broker Configurations. We'll leave the other properties at their default values for the walkthrough, but you should become familiar with all of the Broker config and database properties. Run the RMAN utility and connect to the target (primary) and auxiliary (new standby). The behavior of the broker if the master observer fails depends on whether the broker configuration has one observer or multiple observers. POTENTIAL DATA LOSS: Fast-start failover is enabled with some data loss. Neither the primary database nor the logical standby database needs to be restarted after the switchover completes. Reenabling Disabled Databases After a Role Change describes how to do this. Figure 6-1 Relationship of Primary and Standby Databases and the Observer. For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. In the restore stage, Flashback Database restores the database to a point prior to the standby_became_primary_scn using the before-image blocks in the Flashback Database logs. directory has the same permissions as its parent directory. present, you must start the observer manually using the following Client-side broker receives redo data from a far sync instance. 1 second. Oracle Database PL/SQL Packages and Types Reference, Stop the observer from any computer system in the broker configuration, as described in, Start the observer on the new computer system, as described in Step 8 of, Enable fast-start failover using the DGMGRL, Shut down the primary database and the target standby database using either DGMGRL, Oracle Database Global Data Services Concepts and Administration Guide, Oracle Real Application Clusters Administration and Deployment Guide, Configure the connect descriptor for connect-time failover. file, observer runtime data file (fsfo.dat), fast-start failover callout by the current operating system user who is running DGMGRL The subdirectories After the restart, Redo Apply begins applying redo data from the new primary required permissions, fast-start failover callouts will fail. Issue the DISABLE FAST_START FAILOVER command or the DISABLE FAST_START FAILOVER FORCE command. STANDBY>connect /@STAN as sysdba Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). Read-Only Standby and Active Data Guard . Data Guard Broker Failover - DBA Genesis Support alter database set standby database to maximize availability; If you don't already have a standby database, use your favorite method to create one. Broker will verify that the configuration meets all prerequisites before enabling FSFO and will report any problems it finds. Note that these properties only affect whether primary shutdown and automatic reinstatement are performed if a fast-start failover occurs because the primary crashed or was isolated from the observer and target standby database. This specifies how often the observer establishes a new connection to the primary database. The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g. One is the master Broker will set the primary to use asynchronous log transport by default. When the primary database and the (non-target) standby database regain network connectivity, the broker will propagate its current fast-start failover setting (ENABLED or DISABLED) to the non-target standby. This allows for redundancy in your Data Guard observer setup as well. Regards, Narottam Tagged: dataguard dba rac Welcome! alter system set standby_file_management=auto; This parameter must be set before the primary can be opened in Maximum Availability mode. Make sure that your OS environment on the standby is setup. Reenabling Disabled Databases After a Role Change describes how to restore their viability as standby databases. DGMGRL> show configuration Configuration - CDB01_fraad1_CDB01_fraad3 Protection Mode: MaxAvailability Members: CDB01_fraad1 - Primary database CDB01_fraad3 - (*) Physical standby database Complete Failovers in Configurations Using Cascaded Standbys. DGMGRL to manage multiple observers on multiple configurations. Oracle also provides Fast Application Notification (FAN) for OCI clients and Fast Connect Failover for JDBC clients. configuration file, such as START OBSERVING, If the primary is unable to contact the standby after a user specified period of time (NET_TIMEOUT option of log_archive_dest_ n), it drops out of synchronous transfer mode and begins operating as though it were in Maximum Performance mode. Broker Configuration Has Only One Registered Observer. For more information, see SET MASTEROBSERVER TO. Moorestown, New Jersey, United States. Stops Redo Apply or SQL Apply on the standby database immediately, without waiting until all available redo data has been applied. irrespective of its content, indicates that the script executed successfully. Check the database role,open_mode in standby server. learning with R and Python are also covered in this step-by-step tutorial. 2. You cannot create the standby DB system in a different AD from the primary DB system. Oracle 19c-Performing Dataguard Switchover Using DGMGRL Utility