WAIT option, broker waits for the amount of Stopping the observer does not disable fast-start failover. command for more information about starting the The failover was to a logical standby database. If there are multiple observers, then only one of them is the master observer. The master observer cannot connect to the target standby database, What Happens if the Observer Fails? Performing failover : Step 1: Check Standby Database role. To start an observer as a background process, use the DGMGRL Here's a one-liner observer startup for *nix. Observer uses the value of the DGConnectIdentifier property to connect to and monitor the primary and target standby databases. Broker can be configured to initiate failover on any of the following conditions. See "Database Service Configuration Requirements" for additional information about how the broker interacts with Oracle Restart. A normal shutdown uses SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL. primary. The example assumes that the standby uses the same directory structure as the primary. Manual failover can be performed even if the pre-condition checks are not met. The services required on the primary database are: Log Writer Process (LGWR) - Collects redo information and updates the online redo logs. Table 6-1 Content of Default Directory for Client-side Files, Contains the observer configuration file that is used by 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. The walkthrough begins with a single database that will become the primary of a Data Guard configuration. Default value is 100 After the patch has been successfully applied to all databases, take the following steps to enable fast-start failover and start the observer. SHOW OBSERVER command to confirm that the switch took place. 11.2 rac servicefailover 2020-01-28 ORACLE ORACLE RAC/ASM RAC112. The target standby database is enabled and is in the APPLY-ON state. They must be re-created before they can serve as standby to the new primary database. services. directory has the same permissions as its parent directory. Once an immediate failover is started, the broker: Verifies that the target standby database is enabled. On primary database NORTH, execute the following: On standby database SOUTH, execute the following: Services that are to be active while the database is in the physical standby role must also be created and started on the current primary database regardless of whether the service will be started on that database or not. However, re-enabling Flashback Database will require a bounce since the database must be mounted and not open. 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). Ensure SPFILE is used SQL> sho parameter spfile 2. Automatic failover quickly and reliably fails over the standby Autonomous database to the primary database role, without requiring you to perform any manual steps. This includes the following: broker configuration is in UNSYNC or LAGGING state or unobserved state, failover target is invalid, reinstatement is in progress, or a master observer switch is in progress. lower detection times for primary database failures. These commands can be issued from the DGMGRL command line, but it is not necessary to log on prior to using them. FSFO builds upon a number of other Oracle technologies and features such as Data Guard, Flashback Database, and Data Guard Broker. You might, for instance, use this to allow the observer to monitor the databases using the same connect identifiers as the client applications. For more information, see START OBSERVER IN BACKGROUND. So SALESRW will start on CHICAGO (which is now the primary) and SALESRO will start on BOSTON (which is now the physical standby). In order for Flashback Database to succeed, there must be sufficient history available in the Flashback Database logs and all of the redo generated between the restore point and the standby_became_primary_scn must be available. To configure fast-start failover in observe-only mode: Fast-start failover will not be triggered if the primary or standby database is shut down normally. To allow the database to register with the Data Guard listener, the listener endpoint must be added to the database's local_listener parameter. In 10g, a single wallet can be used for multiple observers, but they must all use the same SYS password. Use the 'show fast_start failover' command to see which user configurable FSFO failover conditions are in effect. 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. US Coast Guard Auxiliary. configuration named ConfigurationSimpleName. You can query the V$FS_FAILOVER_STATS view on the primary database to display statistics about fast-start failovers that have occurred on the system. Initiate the failover on the standby database STAN: once the target standby database's redo applied point is no longer lagging behind the primary Reinstate the former primary database as a new standby database. To do this, use the SET ObserverConfigFile and SHOW ObserverConfigFile commands. lag is less than or equal to the value specified by the 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. This guide uses the naming convention of appending an underscore followed by a letter to the db_name to create the db_unique_name. (Note that the target standby cannot be a far-sync instance. property. Configure Data Guard Broker to manage and monitor the Data Guard configuration. 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. You must provide a connect identifier, through which one or more databases in a specific broker configuration can be reached. If the target is a snapshot standby database, the broker first converts the database to a physical standby database. Conditions shown in blue are enabled by default. If fast-start failover is initiated, the master observer verifies the target standby database is ready to fail over to the primary database role. Immediate Failovers in Configurations Using Cascaded Standbys. 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. A broker configuration can belong to multiple groups. 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. The Overall Steps:-. For example: The following example shows the fast-start failover information for the DRSolution configuration: The following SHOW OBSERVER command displays information about multiple observers in the DRSolution broker configuration. Then set the configuration protection mode to maximum availability. Group definition this section is optional. The broker will not allow a switchover to a standby that has an apply delay configured (DelayMins property is set to a non-zero value). The default value is ALL. Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. databases (PDBs) on any of the instances. The broker preserves the protection mode that was in effect prior to the failover. Determine the number and size of the Online Redo Log files (ORLs). created when the START OBSERVER command is issued. The configuration status returns the SUCCESS status after the observer reestablishes its connection to the primary database, which then notifies the target standby database. drain_timeout amongst the active services. If the configured data loss guarantee cannot be upheld, SQL>SHUTDOWN IMMEDIATE; If there is only one observer, then it is considered to be the master observer. For example, if the old standby was a physical or snapshot standby, then the old primary must be re-created as a physical standby. Note the use of "/@" to login using the wallet. Don't initiate failover unless at least 30 minutes of history is available. A single-instance database must be registered with Oracle Restart in order to publish FAN events via ONS. What is true about Data Guard setup with fast-start failover? The reinstated database acts as the fast-start failover target for the new primary database, making a subsequent fast-start failover possible. The failed primary database requires reinstatement as a new standby database to the new primary. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. 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. Subsequent changes to the same block during the same snapshot are not recorded. The targets are referred to as candidate targets. Any unsent redo data residing on the far sync instance is transmitted to the target physical standby prior to converting the physical standby into a primary database. To enable fast-start failover with DGMGRL, issue the ENABLE FAST_START FAILOVER command while connected to any database in the broker configuration, including on the observer computer. If the database is managed by Oracle Clusterware, broker does not open any of the Observers should be installed and run on a computer system that is separate from the primary and standby systems. You want to prevent fast-start failover from occurring because the primary database will resume service soon. When you run commands that need access to the observer Opens the new primary database in read/write mode. More specifically, we can have an asynchronous second read-only Managed instance in the same or in a different region. The master observer waits the number of seconds specified by the FastStartFailoverThreshold configuration property before attempting a fast-start failover when the primary database has crashed or has lost connectivity with the observer, as in the following situations: The primary database loses its connections with both the observer and target standby database. If you expect the network to be disconnected for a long time and This is because the -role qualifier is taken into account only by Data Guard broker, and at database startup. Tasks that must be performed before and after a fast-start failover The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. 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. The connect-identifier is a TNS alias defined in tnsnames.ora through which all instances of all databases in this Data Guard broker configuration can be reached. You can upgrade the protection mode later, if necessary, as described in Setting the Protection Mode for Your Configuration. Displays when the target standby database does not have all of the primary database redo data and the configuration is operating in maximum availability mode. We will create 4 SRLs starting with group# 11. specified, the file is stored in an appropriate directory under the broker's Complete Failovers in Configurations Using Far Sync Instances. There is no impact on your current configuration or on applications. On the Oracle Data Guard Overview page, click Database must be reinstated. Enable Fast-Start Failover Using Cloud Control. Verify the configuration from both hosts. is only possible when the configured data loss guarantee can be Issue the following command while connected to any database in the broker configuration, except the database that is to be reinstated: The newly reinstated standby database will begin serving as a standby database to the new primary database. You need to consider all of the options at the time you are building your Oracle Data Guard configuration, including factors such as the characteristics of physical standbys versus logical standbys versus snapshot standbys, the network latency to your standby database sites, the computing capabilities at a future primary database site, and so on. The Column Value in the following table is consistent across instances in an Oracle Real Applications Clusters (Oracle RAC) environment. The new primary database is opened in read/write mode and redo transport services are started. https://www.facebook.com/dbahariprasath/? 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. Fast-start failover will not occur unless all instances comprising the Oracle RAC primary database are perceived to have failed. Use the FastStartFailoverTarget configuration property on the current primary database to specify one or more fast-start failover targets. fast-start failover, you can issue the DGMGRL SHOW FAST_START FAILOVER, In the previous article, we have seen switching the role of Primary and standby database and failover Primary role to Standby database manually. 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). alter database recover managed standby database finish; alter database activate standby database; Managed recovery process has been stopped between primary and standby database and standby becomes primary database. If clients are already configured to automatically time out and reconnect if they don't get a response from the database, a simple but effective approach is to use a network alias (e.g. Note: Data Guard requires dedicated server connections for proper operation. Credentials Required for Access to Broker Configurations. You cannot perform a manual failover to the target standby database for the same reason. Now it will return PRIMARY. Being FSFO ready means that all conditions are met for a successful failover, including having a running observer and sufficient redo transmitted to the failover target to meet durability requirements. In a complete failover, it is also possible to failover to a standby database (terminal standby) that gets redo from another standby database (cascader). collections and databases Set up replica sets and automatic failover in MongoDB Use sharding to scale horizontally, and learn how . CONNECT command. If the designated fast-start failover target develops a problem and cannot be the target of a failover, then the broker automatically changes the fast-start failover target to one of the other candidate targets. The default name for That process is shown here. Stops Redo Apply or SQL Apply on the standby database immediately, without waiting until all available redo data has been applied. SQL Apply on all other bystander standby databases automatically begin applying redo data received from the new primary database. Before a Staff support, hardware and software, security (both software and site), network connections, and bandwidth should be equivalent at both sites. The broker continuously monitors for all sessions that are connected For Fast Connection Failover (FCF) to occur, a client must be able to locate the new primary database after a failover. If the database is not managed by Oracle Clusterware, They cannot be reinstated. You must ensure that the primary database is shut down prior to performing a manual failover. Oracle Data Guard helps you change the role of databases between primary and standby using either a switchover or failover operation. This action may result in two databases in the configuration simultaneously assuming the primary database role should fast-start failover occur. For a system to process an instruction involving data access, these are the certain steps involved: Fetch the block of data from the hard disk (secondary/permanent storage) to the primary memory (e.g. This add service command. We'll start it interactively for now to verify that everything's working. This list describes restrictions when fast-start failover is enabled. Oracle Database 10g databases running versions prior to 10.2.0.4 will remain in a stalled state until aborted or signaled to remain the primary by the observer once connectivity has been restored. If you re-create the old primary database, it must be created as the standby type of the old standby database. Use Recovery Manager (RMAN) to back up the PeopleSoft database on a regular backup schedule. In this mode you will need to consider how much data loss is acceptable in terms of seconds and set the FastStartFailoverLagLimit configuration property accordingly. To protect the files, it's good practice to store them in separate filesystems. If there is more than one standby database in the configuration, you must explicitly set the FastStartFailoverTarget property on the primary database to name one or more candidate target standby databases. ORACLE instance shut down. 4. 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. 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. They must be re-created from a copy of the new primary database. Each database in a Data Guard configuration must have a unique name. The simplest way to do this is to abort the primary. directory by this environment variable does not exist, or the $DG_ADMIN The FS_FAILOVER_STATUS column in the V$DATABASE view for the target standby database displays a reason why fast-start failover cannot occur. Except for testing purposes, it is not recommended that you start more than one observer on the same host for a Data Guard broker configuration. The broker selects a target based on the order in which they are specified on the FaststartFailoverTarget property. It behaves similarly to START OBSERVING and STOP OBSERVING to operate on all the configurations defined in the observer configuration file. 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. Create a unique connect alias for each database. The RedoRoutes property on the primary if the new value would result in the primary not being able to ship redo to the current fast-start failover target standby. You can also specify a list of ORA- errors that will initiate FSFO failover. failure on the primary database. For each temporary table, verifying that temporary files associated with that table on the primary database also exist on the standby database. Role Transitions: Switchover and Failover 1 -7 Oracle Data Guard Broker Framework 1 -9 C hoosing an Interface for Administering a Data Guard Configuration 1 -10 Oracle Data Guard: Architecture (Overview) 1 -11 Primary Database Processes 1 -12 . If the The broker initiates a failover after the number of seconds specified by this Starting with 10.2.0.4 (including all versions of 11g and later), Oracle provides the FastStartFailoverPmyShutdown Broker property that allows you to specify what the primary should do if it is still in a stalled state when the FSFO threshold timeout has elapsed. all of the same type (all physical or all logical standby databases), choose the standby 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. the Steps To Congure Oracle 11g Data Guard Physical Standby associate that we give here and check . Provides an automatic failover The most common problems are mismatched Data Guard protection modes and LogXptMode properties and forgetting to enable Flashback Database on the primary or standby. In an Oracle Data Guard configuration, the SRVCTL -startoption for a standby database is always set to OPEN after a switchover. 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. This can be done regardless of whether the failover was done to a physical, logical, or snapshot standby database. Fast-start failover enables the Data Guard broker to rapidly and automatically failover to a previously chosen standby database without requiring manual intervention. November 20, 2009. time, if all the sessions that are connected though the active services Getting the Oracle Net configuration right is one of the key factors in a successful FSFO deployment. All database connections associated with the observer, including the initial connection, must use dedicated server connections. Event notification and database connection failover support is available to database clients connected to local database services when a broker-managed failover occurs. On Linux/Unix, the directory specified by the DG_ADMIN environment Create a wallet and set the default username and password to the database's SYSDBA credentials (usually SYS). If the broker performs a switchover or failover, then it starts the service SALESRW or SALESRO based on the current role of the database. Oracle Corporation recommends that you specify this type of failover. isolated. A value of TRUE helps to ensure that an isolated primary database cannot satisfy user queries. ConfigurationSimpleName. 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. However, there may be situations in which you must disable fast-start failover when Verify the target standby database is ready for failover. Any apply delay must be removed before beginning a switchover. fsfocallout.ora and they have the required permissions. The minimum value of ObserverPingInterval is 100 At this point, you can either: Disable fast-start failover (described in Disabling Fast-Start Failover) and attempt to open the former primary database, Manually reinstate the former primary database, as described in Reenabling Disabled Databases After a Role Change. Clusterware agent that the failover completed, the Oracle Clusterware agent opens PDBs there is a lost network connection, be aware that the observer may attempt a To proceed, you must first disable fast-start failover using the FORCE option, and then perform a manual failover. 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). In START OBSERVING [cfg_group_name] starts a new observer for each broker configuration in the specified group. This directory is created when you run the Step:6 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. FSFO can also be used with logical standbys and an FSFO-enabled configuration may have multiple standbys with a mix of physical and logical, but only one standby can be the failover target at any given time. After a switchover completes, the broker preserves the overall Oracle Data Guard protection mode as part of the switchover process by keeping the protection mode at the same protection level (maximum protection, maximum availability, or maximum performance) it was at before the switchover. You cannot perform a switchover to a snapshot standby database unless you first convert it back to a physical standby database. 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. $DG_ADMIN directory. When the standby becomes available again, the primary and standby re-synchronize and resume synchronous redo transfer. the observer was killed after the stall began, but before the failover timeout had elapsed). Note that the value of the FastStartFailoverPmyShutdown configuration property must be FALSE for the primary to stall indefinitely under these conditions. The connect descriptor can be configured in one of two ways: Oracle Database PL/SQL Language Reference for more information about the DB_ROLE_CHANGE system event. There is little risk in enabling Flashback Database to determine its storage requirements - it can be disabled while the primary is open if necessary. For more information, see SET MASTEROBSERVER TO. Provides an automatic failover environment 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. In the event of a You The Oracle Database 10g FSFO observer is limited to using the default username and password defined in the wallet. database. 2. post-callout script, and pre-callout success file for the broker If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. The old Primary must have been running in flashback mode before the failover. database (if real-time query is enabled). Fast-start failover will not be attempted for the other types of database shutdown (NORMAL, IMMEDIATE, TRANSACTIONAL). 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. In an environment where there are multiple observers configured, stopping the master observer is not allowed unless it is the last running observer. In order to accommodate all load conditions, Oracle recommends having at least one more SRL group than the number of ORL groups of the same size. STAN is now transitioned to the primary database role.Now your PHYSICAL STANDBY Database has become PRIMARY. Refer to the appropriate Oracle RAC or Oracle Restart documentation for further information. This lets you take advantage of the broker's The following sections describe how to reinstate or reenable a database. ob2-host can be a master observer when