These are the guidelines for choosing a target standby database. Conditions shown in blue are enabled by default.
Switchover and Failover with DataGuard Broker on Oracle 19c - Data Alchemy 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. We'll start with switchovers. The physical and snapshot standby databases will have to be re-created from a copy of the new primary database. See Disabling Fast-Start Failover. The new primary database is opened in read/write mode and redo transport services are started. Staff support, hardware and software, security (both software and site), network connections, and bandwidth should be equivalent at both sites. See "Database Service Configuration Requirements" for additional information about how the broker interacts with Oracle Restart. 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. 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. Transitions the target standby database into the primary role, opens the new primary database in read/write mode, and starts redo transport services. If you perform a manual failover when fast-start failover is enabled: The failover can only be performed to the current target standby database. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. The time interval specified by the FastStartFailoverThreshold property is ignored if the master observer detects that a user-configurable condition has occurred or if a fast-start failover has been requested by the DBMS_DG.INITIATE_FS_FAILOVER function. 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). Oracle Data Guard Command-Line Interface Reference for more information about these broker commands. directory specified by this variable does not exist, or the directory does not have the the ObserverPingRetry and ObserverPingInterval properties to achieve This action may result in two databases in the configuration simultaneously assuming the primary database role should fast-start failover occur. You must manually re-create the database as a standby database and then reenable it. If the target is a snapshot standby database, the broker first converts the database back to a physical standby and then starts Redo Apply to apply all the accumulated redo before completing the failover and opening the database as a primary database. Start the Data Guard listener on both "a" and "b" hosts. For manual failover, the observer is started and communicating with the target standby database. Client-side broker To start an observer as a background process, use the DGMGRL For switchovers, understanding all of the factors can simplify the choice of which standby database to consider as your new primary database. command on the observer computer: The observer is a continuously executing process that is Note that the new primary database does not need to be restarted. However the target can receive redo from a far sync instance.). The broker preserves the protection mode that was in effect prior to the failover. Enabling Fast-Start Failover Task 1: Determine Which of the Available Standby Databases is the Best Target for the Failover, Enabling Fast-Start Failover Task 2: Specify Target Standbys with the FastStartFailoverTarget Configuration Property, Enabling Fast-Start Failover Task 3: Determine the Protection Mode You Want, Enabling Fast-Start Failover Task 4: Set the FastStartFailoverThreshold Configuration Property, Enabling Fast-Start Failover Task 5: Set Other Properties Related to Fast-Start Failover (Optional), Enabling Fast-Start Failover Task 6: Enable Additional Fast-Start Failover Conditions (Optional), Enabling Fast-Start Failover Task 7: Using DGMGRL or Cloud Control, Enabling Fast-Start Failover Task 8: Start the Observer, Enabling Fast-Start Failover Task 9: Verify the Fast-Start Failover Environment. the location of the observer log file, and the location of the observer runtime data For more details about managing Redo Apply services using properties, see Managing Log Apply Services. Oracle Data Guard work on two database roles Primary and Standby. If the Broker configuration is changed to make a bystander the new failover target (probably a good idea if the failed database will be down for a while), the observer will not automatically reinstate the former primary because it is no longer part of the FSFO configuration. Enabling fast-start failover in a configuration operating in maximum performance mode provides better overall performance on the primary database because redo data is sent asynchronously to the target standby database. ConfigurationSimpleName is created. 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". There is no impact on your current configuration or on applications. If you cannot tolerate any loss of data, then ensure that the configuration protection mode is set to maximum availability or maximum protection. observer, whether it is currently connected to the primary and target standby databases, To restore your original disaster-recovery solution after switchover to a logical standby database or after failover to any standby database, you may need to perform additional steps. Immediate Failovers in Configurations Using Cascaded Standbys. During an immediate failover, the broker performs the failover steps described in How the Broker Performs an Immediate Failover Operation. If the agent is not Depending on the failover and the types of standby databases involved, some of the databases may need to be reinstated or re-created. Make sure the last redo data transmitted from the Primary database was applied on the standby database. Automatic failover quickly and reliably fails over the standby Autonomous database to the primary database role, without requiring you to perform any manual steps. Install the DGMGRL command-line interface on the observer computer as described in Oracle Data Guard Installation. Alternatively, you can query the V$DATABASE view on the target standby database. Chapter 9 of the Data Guard Broker documentation (10g and 11g) contains a description of each property. There can be up to four FB Group:https://www.facebook.com/groups/894402327369506/ Synopsis. This allows the appropriate Data Guard services, such as redo transport or redo apply, to be started when the database is restarted later for any reason. alter database recover managed standby database cancel; Step:3 The below commands will help to bring up standby as primary. Database dismounted. . Each group that you define must have at least one broker configuration. The FastStartFailoverTarget configuration property on the primary unless the new property value contains the current fast-start failover target. They must be re-created from a copy of the new primary database. Fast-start failover allows the broker to automatically fail over to a previously chosen standby database in the event of loss of the primary database. The lowest possible value is 5 seconds. After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. Data guard Configuration details:- Login in to Standby Server:- Step:1 Check the database role and open_mode Select name,open_mode,database_role from v$database; The failover was to a logical standby database. The observer host is 'observer.demo.org'. Now it will return PRIMARY. The default value is 30 seconds and the lowest possible value is 5 seconds. To allow the master observer to automatically reinstate the former primary database, the database must be started and mounted. The new ConfigurationWideServiceName configuration property can be used to simplify setting up this connect identifier. If the currently configured mode is maximum protection, Cloud Control will downgrade the mode to maximum availability. Enabling fast-start failover does not trigger a failover. Starting with Oracle Database Release 21c, use the DG_ADMIN DGMGRL> show configuration Configuration - CDB01_fraad1_CDB01_fraad3 Protection Mode: MaxAvailability Members: CDB01_fraad1 - Primary database CDB01_fraad3 - (*) Physical standby database WAIT option, broker waits for the amount of 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 . 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. See FastStartFailoverTarget for more information about this property. So SALESRW will start on CHICAGO (which is now the primary) and SALESRO will start on BOSTON (which is now the physical standby). Now let's test switchover in the other direction. The observe-only mode for fast-start failover enables you to test how fast-start failover will work in your environment. primary database. If you performed a failover or switchover that requires you to re-create the failed primary database or standby databases that were disabled during the role transition, then follow the procedures in the Oracle Data Guard Concepts and Administration chapter, "Creating a Physical Standby Database" and also the Oracle Data Guard Concepts and Administration chapter, "Creating a Logical Standby Database.". The total storage requirement is proportional to the number of distinct blocks changed during snapshots - e.g.
A Senior Engineer's Guide to the System Design Interview The SHOW CONFIGURATION command will show you which databases can be reinstated and which databases must be re-created. 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. This prevents a "split brain" condition if a failover occurs since none of the changes made to the isolated primary can be made permanent. To move the observer to another computer: There is no need to disable fast-start failover when you move the observer. These are some points to consider before you begin a switchover. guaranteed to lose no data. In this mode, the FastStartFailoverLagLimit configuration property is set to zero. These tasks assume that you are connected as SYS or SYSDG and that a primary and standby database are already set up in a broker configuration. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. Restarts the new standby (former primary) database if the switchover occurs to a physical standby database, and Redo Apply begins applying redo data from the new primary database. By default, the observer uses the same connect identifiers used by Data Guard for redo transfer and information exchange between the primary and standby ( DGConnectIdentifier in Oracle Database 11g, InitialConnectIdentifier in Oracle Database 10g). See Enabling Fast-Start Failover for more information. Some properties have changed between those releases. A far sync instance or Zero Data Loss Recovery Appliance is not a database and therefore cannot be the target of a role transition. This method will disable fast-start failover on all databases in the broker configuration. If automatic reinstatement fails, the broker will log errors and the former primary database will remain in the mounted state. status before the crash. If possible, confirm that fast-start failover has not A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. It will return PHYSICAL STANDBY, Bystanders are part of the Data Guard configuration, but not part of the FSFO configuration. Controlfile is permanently damaged because of a disk failure. On Linux/Unix, the directory specified by the DG_ADMIN environment
Which three are prerequisites for enabling fast-start failover? This list describes conditions in which the broker cannot automatically reinstate the former primary database. To verify this change, again query the Database_role column of V$DATABASE. (If there are other conditions, unique to an application, that would warrant a fast-start failover then the application can be set up to call the DBMS_DG.INITIATE_FS_FAILOVER function and start a fast-start failover immediately should any of those conditions occur. Metadata for the fuzzy snapshot is stored in the flashback log itself. OBSERVE-ONLY: Fast-start failover is enabled in observe-only mode. an alias of the broker configuration name. This document describes how to setup clients to connect to Data Guard databases (primary and standby) and configure automatic client failover such that in case there is role change due to switchover or . 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. Aug 2022 - Present6 months. This can be done regardless of whether the failover was done to a physical, logical, or snapshot standby database. If you will be using RMAN to create the standby database, it also needs a static service to restart the database being created. To help you select an appropriate switchover or failover target, use the following DGMGRL commands which perform checks on the database to determine its readiness to complete a role change. milliseconds and that of ObserverRetryCount is 10. Do not use Shared Server (formerly MTS) for Data Guard.
Data Guard Failover to physical standby Tips - dba-oracle.com The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs You may failover to a snapshot standby database. The original primary database will be restarted as a part of the switchover operation. You can specify particular conditions for which a fast-start failover should occur using either Cloud Control or the DGMGRL ENABLE FAST_START FAILOVER CONDITION and DISABLE FAST_START FAILOVER CONDITION commands. The VALIDATE FAST_START FAILOVER command can be used to validate a fast-start failover configuration and identify misconfigurations that prevent the initiation of fast-start failover. 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.
PDF Steps To Configure Oracle 11g Data Guard Physical Standby Oracle 12c-Step by Step Manual Data Guard Failover The following sections describe how to perform manual failovers: Reenabling Disabled Databases After a Role Change. These are the actions the broker performs after you start a switchover. Here's a one-liner observer startup for *nix. The same thing happens if a shutdown and startup of either database occurs - the service that is started is the one that matches the role of the database being started. You want to prevent fast-start failover from occurring because the primary database will resume service soon. START OBSERVING [cfg_group_name] starts a new observer for each broker configuration in the specified group. PRIM>SHUTDOWN IMMEDIATE; Data Guard Broker - Controls the creation and monitoring of Data Guard. about starting the observer as a background Reinstatement restores high availability to the broker configuration so that, in the event of a failure of the new primary database, another fast-start failover can occur. The target standby database is enabled and is in the APPLY-ON state. 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. 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. In such a case, no attempt is made to transmit any unsent redo from the cascader to the terminal standby. Applications can initiate FSFO failover directly using the DBMS_DG.INITIATE_FS_FAILOVER procedure with an optional message text that will be displayed in the observer log and the primary's alert log. Any apply delay must be removed before beginning a switchover. Enable Fast-Start Failover Using Cloud Control. Data Guard Switchover/failover to standby The standby database will be activated to serve as the primary database at some point in its life cycle. 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. For example: Fast-start failover occurs if both the observer and the target standby database lose connection to the primary database for the period of time specified by the FastStartFailoverThreshold configuration property. SQL>select sequence#, applied from v$archived_log; You can start, stop, and show observers for a group of configurations. 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. Step:1 Check the database role and open_mode
How we create a failover group in Azure Managed Instance Database services can be configured to be active in specific database roles on Oracle RAC databases and on single-instance databases managed by Oracle Restart. For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. 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. For more information, see SET MASTEROBSERVER TO. Verifies that the primary and the target standby databases are in the following states: The primary database is enabled and is in the TRANSPORT-ON state. operation. Add the primary database and each standby database to the address list. For more information, see START OBSERVER IN BACKGROUND. 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. Note the primary and target standby must have connectivity for this command to complete successfully. In this case, only observers on ob1-host and The information in this guide is based on practical experience gained from deploying FSFO in a global corporate production environment. You must use the Oracle wallet to store the credentials for all broker configurations to be managed. As mentioned above, Maximum Availability mode is mandatory for Oracle Database 10g and optional for Oracle Database 11g. Provides an automatic failover environment 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. Before enabling fast-start failover in data guard broker, the only required precondition is enabling Flashback Database. It uses these databases as a copy of the . To achieve FB Page:https://www.facebook.com/dbahariprasath/? This is true regardless of the settings for the FastStartFailoverPmyShutdown and FastStartFailoverAutoReinstate configuration properties. The default It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. If the switchover occurs to a physical standby database, and the former primary An existing connection which is already closed from the database side would throw an error. This file When running the START If the service has been configured to start automatically (-policy AUTOMATIC), then the service will automatically start only after a database role change. The failover time is dependent upon whether the target standby database (physical or logical standby database) has applied all of the redo data it has received from the primary database. The observer automatically starts the reinstatement process. You can also reinstate bystander standby databases that were disabled during a failover operation. After the fast-start failover completes successfully, the master observer will attempt to reinstate the former primary database as a new standby database when a connection to the former primary database is reestablished, and the FastStartFailoverAutoReinstate configuration property is set to TRUE. The remaining observers are called backup observers.
Albino DeSantis - Senior System Engineer - US Coast Guard - LinkedIn fsfocallout.ora. Were sorry. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by This is called failover. In an immediate failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). 1. What is true about Data Guard setup with fast-start failover? What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? required permissions, DGMGRL reports an error. For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role. Steps to Create a Physical Standby Databa se 3 -3 Preparing the Primary Database 3 -4 FORCE LOGGING . observer on ob1-host will be given priority over Initiate the switchover on the primary database PRIM: What is true about data guard set up with fast-start failover (FSFO) in Oracle Cloud Infrastructure (OCI)? SHOW ObserverConfigFile used to check the runtime property ObserverConfigFile. Prepare the primary database in advance for its possible future role as a standby database in the context of the overall protection mode (see Managing Data Protection Modes). Indexing is a mechanism by which the underlying data is mapped for faster retrieval. But it will also continue trying to reconnect to the primary database indefinitely.
How to Enable Fast-Start Failover in Oracle Data Guard issue commands and interact with the broker configuration. If you expect the network to be disconnected for a long time and Installing and starting an observer is an integral part of using fast-start failover and is described in detail in the following sections: Oracle Data Guard Installation explains that you can either install only the Oracle Client Administrator or you can install the complete Oracle Database Enterprise Edition or Personal Edition on the observer system. An observer is an OCI Without the credentials, Broker will complete the role transition, but will leave the databases in need of a manual restart. The following table summarizes which standby types are supported in which protection modes when fast-start failover is enabled. distance. Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. 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. If the failover fails for any reason, it could leave the target standby database inoperable, regardless of whether the target standby database is ready to failover.