The default name of the callout configuration file is STOP OBSERVING [cfg_group_name] stops LOCAL observers running on this host (where this DGMGRL is running) for all broker configurations in a specified group. The This list describes conditions in which the broker cannot automatically reinstate the former primary database. To see Manual Switch Over Manual SwitchOver in Oracle To see Manual Fail Over Manual Failover in Data Guard With Oracle Data Guard [] 5. This allows Data Guard to remain functional during maintenance periods when the application listeners are down. ConfigurationSimpleName. These facilities allow applications written to take advantage of them to receive asynchronous notification of database events, including role transitions. What is true about Data Guard setup with fast-start failover? expires. For example: In the following example, assume the network between the primary database and the observer has failed. Starts redo transport services to begin transmitting redo data to all bystander standby databases that were not disabled. For zero data loss in maximum availability mode, the FastStartFailoverLagLimit property must be set to zero. When restarting the databases, you may restart them in any order. Whenever possible, you should switch over to a physical standby database: If the switchover transitions a physical standby database to the primary role, then: The original primary database will be switched to a physical standby role. Problems with automatic reinstatement are frequently due to misconfiguration, so let's look at this in a bit more detail. We will create 4 SRLs starting with group# 11. If the primary and target standby databases do not have network connectivity or if the database to which you are connected does not have network connectivity with the primary database, consider using DISABLE FAST_START FAILOVER with the FORCE option. File. the observer on ob2-host to become the master When DGMGRL starts, if the DG_ADMIN DGMGRL> show configuration Configuration - CDB01_fraad1_CDB01_fraad3 Protection Mode: MaxAvailability Members: CDB01_fraad1 - Primary database CDB01_fraad3 - (*) Physical standby database Create a pre-callout script, or a post-callout script, or both. So if the original Primary database is still accessible, you should always consider a switchover first. Once you set these properties, their values persist through role changes during switchover and failover. Using the db_unique_name of each database as the Oracle Net alias is simple and intuitive. The observer does not attempt to reinstate the former primary database. Data Guard Broker - Controls the creation and monitoring of Data Guard. Disabling fast-start failover does not stop the observer. If fast-start failover is disabled, then manual failover may still be possible. The primary and target standby must have connectivity for the STOP OBSERVER command to complete successfully. Now it will return PRIMARY. Broker will set the primary to use asynchronous log transport by default. To avoid the overhead of recording every change to every block, Flashback Database takes a "fuzzy" snapshot every 30 minutes and only records the before-image block upon its first change since the last snapshot. For Active Oracle Data Guard, it will fail to open up a connection unless its in read-only mode. file, observer runtime data file (fsfo.dat), fast-start failover callout The primary database was shut down without using the ABORT option. The primary database must be running in order to start the observer. Dataguard broker is used to automate monitoring and controlling standby setups. Otherwise, they must be re-created from a copy of the new primary database. As shown in the table, fast-start failover can be enabled in maximum availability Written by authors well-known for their talent with RAC, Pro Oracle Database 11g RAC on Linux . When running the START Reference architectures for Oracle databases on Azure - Azure Virtual If both of those observers are unavailable, the observers It is possible to manually perform a completer failover to a standby database that receives redo data from a far sync instance. SHOW OBSERVER command to confirm that the switch took place. See the START OBSERVER If there is only one standby database in the configuration, you can skip this step and continue with Task 3. This walkthrough assumes that all ORLs and SRLs on the primary and standby databases are the same size. Permissions Required by the DG_ADMIN Directory. Reinstate the former primary database as a new standby database. SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH; For example, if all your physical standbys are also unavailable, then failing over to a logical standby is your only choice. Physical Standby Database SWITCHOVER & FAILOVER Operations In the following example commands, a service named PAYROLL is configured to be active in the PRIMARY role on the primary database NORTH. This section lists the steps the master observer takes to determine if a fast-start failover is needed and then to perform one, if necessary. The FS_FAILOVER_OBSERVER_PRESENT column, which indicates whether the observer is running and actively pinging the database. The reduced need for manual intervention can increase availability without increasing management costs. Errors occurring for any other configuration members will not impede the switchover. Perform a switchover to a standby database that is not configured as the fast-start failover target, Perform a switchover to the target standby database in a configuration operating in maximum availability mode, unless the standby database is synchronized with the primary database, Perform a switchover to the target standby database in a configuration operating in maximum performance mode, unless the standby database is within the lag limit of the primary database. If there is only one observer, then it is considered to be the master observer. An observer is a separate OCI client-side component that run on a different computer from the primary and standby databases and monitors the availability of the primary database. Oracle recommends configuring Flashback Database on every database so that if failover occurs to a physical standby database, you can more easily reinstate any disabled standby databases. Multiplexing SRLs merely adds unnecessary IO and can increase commit latency. This page will not allow you to alter the protection mode. (Snapshot standbys are not included in the table because they are not supported as fast-start failover targets.). See Choosing a Target Standby Database for helpful advice. FSFO uses Flashback Database as part of the process of reinstating a failed primary as a standby. the preferred method for starting an observer. If the primary database can be mounted, it may be possible to flush any unsent redo data from the primary database to the target standby database using the ALTER SYSTEM FLUSH REDO SQL statement. Note: If you have just enabled archivelog mode, force an archive log creation ( alter system archive log current) to ensure that at least one archive log exists. The information in this guide is based on practical experience gained from deploying FSFO in a global corporate production environment. The list is empty by default. The broker verifies the state and status of the databases to ensure that the switchover transitioned the databases to their new role correctly. Staff support, hardware and software, security (both software and site), network connections, and bandwidth should be equivalent at both sites. This list describes restrictions when fast-start failover is enabled. Verify the configuration from both hosts. If it's not, DGB will not allow the failover to continue until the DBA has manually resolved any discrepancies. 2. by the current operating system user who is running DGMGRL The subdirectories While this eliminates the processing overhead associated with periodically establishing a new observer connection to the primary database, it also prevents the observer from detecting that it is not possible to create new connections to the primary database. The subcommands for this verb include start, stop, setMaster, show, and delete_alternate_observer. Reinstate the original primary database to act as a standby database in the new configuration. If you don't already have a Flash Recovery Area (FRA), you will need to create one for Flashback Database. Once Flashback Database has succeeded, the observer will convert the database to a standby, bounce it, and begin apply services. 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. Start the observer by running dgmgrl and logging in using SYS credentials. In this mode, no actual changes are made to your Broker configuration. Data Guard | Oracle disable fast-start failover with the FORCE option on the This document only talks about switchover involving physical standby database. After setting local_listener, register the database with the listener and verify the services have been registered. For information about event notification and database connection failover support for global services, see the Oracle Database Global Data Services Concepts and Administration Guide. To see the specific parameter, use the "show database StatusReport" command. Once the observer is started, you cannot change the file's name and location. The ObserverPingInterval The master observer never waits for the threshold to expire to perform a fast-start failover in the following situations: If the master observer determines that any of the user-configurable conditions has been detected, then it attempts a fast-start failover. You must ensure that the primary database is shut down prior to performing a manual failover. A complete failover can occur without any data loss, depending on the destination attributes of redo transport services, but an immediate failover usually results in some data loss. These The FS_FAILOVER_STATUS column in the V$DATABASE view for the target standby database displays a reason why fast-start failover cannot occur. If the new primary database was a primary database in the past, and had block SQL>ALTER SYSTEM SWITCH LOGFILE; How To Use Local Data Processing and Oracle Data Guard for Source MASTEROBSERVERHOSTS, DGMGRL reports an error if the 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. Once the primary database regains connectivity with the target standby database, fast-start failover will be disabled for all the databases in the configuration. directory does not have the required permissions. 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. STANDBY>ALTER DATABASE OPEN; Note the use of "/@" to login using the wallet. See Troubleshooting Problems During a Switchover Operation for more information. That is, if the observer is connected to any instance in the Oracle RAC, all instances will show a value of YES. If a group name is not specified, then SHOW OBSERVERS alone is also a valid command. After the former primary database has been repaired, the observer reestablishes its connection to that database and reinstates it as a new standby database. redo generation on the primary database will be stalled. 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. What to do in case of failover: (Important note: Istanbul is the primary server and Baku is the standby server) 1. It's generally a good idea to store the state file in a directory associated with the database to avoid locking issues when running multiple observers on the same host. Verify Before Switch-over: files are stored in subdirectories of the DG_ADMIN directory. Default value is 10 miliseconds. This prevents a "split brain" condition if a failover occurs since none of the changes made to the isolated primary can be made permanent. So SALESRW will start on CHICAGO (which is now the primary) and SALESRO will start on BOSTON (which is now the physical standby). Note: You can also use TNS aliases defined in the tnsnames.ora file when setting the local_listener parameter. Clusterware: The broker notifies Oracle Clusterware to stop active When you are experiencing network disconnections and you issue the DISABLE FAST_START FAILOVER FORCE command on the primary database or a standby database that does not have connectivity with the primary database, fast-start failover may not be disabled for all databases in the broker configuration. We'll start with switchovers. You cannot create the standby DB system in a different AD from the primary DB system. The OberverPingRetry property specifies the number of 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. However, there may be situations in which you must disable fast-start failover when . configuration named ConfigurationSimpleName. How to switch roles in Oracle Data Guard - The Geek Diary 99 Software Similar To Oracle Data Guard Backup & Sync 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. After an immediate failover completes, all the standby databases in the configuration, regardless of their type, are disabled. The primary database can be reinstated if it had flashback database enabled. 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. In addition to setting the configuration protection mode to maximum performance, you will also need to ensure that the LogXptMode database property for both the primary and target standby database is set to ASYNC. Most in-progress failures cannot be restarted (for example, archived redo log file corruption on the primary database). observer on ob1-host will be given priority over Data Guard Failover to physical standby Tips - dba-oracle.com Reenabling Disabled Databases After a Role Change describes how to do this. environment that is guaranteed to either lose no data (when the Transitions the target standby database into the primary database role, as follows: Changes the role of the database from standby to primary. observers are registered, a directory named If fast-start failover is enabled and the Datafile Write Errors condition is specified, then a fast-start failover is initiated if write errors are encountered in any data files, including temp files, system data files, and undo files. The observer does not need to coordinate fast-start failover when fast-start failover is disabled, so the primary and target standby do not nominate a master observer until fast-start failover is enabled. FastStartFailoverLagLimit configuration property is set to zero) or You cannot perform a switchover to a snapshot standby database unless you first convert it back to a physical standby database. on particular instances based on the service configuration.