START OBSERVER IN BACKGROUND

The START OBSERVER IN BACKGROUND command starts a fast-start failover observer on this host (where this DGMGRL session is running) as a background process.

After this command is issued, DGMGRL reports whether the START OBSERVER IN BACKGROUND command submitted successfully. If yes, then control returns to the user. (This is different behavior from the START OBSERVER command, in which control does not return to the user after the observer is started.)

This command uses Oracle wallet to obtain credentials to log into the database server and register observers. 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. If the wallet is not configured, then the command will fail to start the Observer.

Format

START OBSERVER [<observer_name>] IN BACKGROUND CONNECT IDENTIFIER IS <connect_identifier> [FILE IS <observer_file>] [LOGFILE IS <log_file>] [TRACE_LEVEL IS USER | SUPPORT];

Command Parameters

observer_name
The name to identify observers within the same data guard broker configuration.

  • No two observers on the same Data Guard Broker configuration can have the same name.

  • If no name is specified for the observer then a default observer name, the host name of machine where the START OBSERVER command is issued, is used.

  • An observer name is case-insensitive.

  • The string "NONAME" cannot be used as an observer name.

connect_identifier
The connect identifier will be used to find the credentials in an Oracle wallet to connect to a member in the configuration.
observer_file
Specifies the path and name of the runtime data file. If not specified, then the file name defaults to fsfo.dat and the path is the current working directory.
log_file
The full path of the observer log file. Each observer has its own log file.

Usage Notes

  • Even if the START OBSERVER command is submitted successfully, the observer might fail to start due to credential problems, intermittent network connections, or failure on observer registration. To verify that the observer started successfully, use the SHOW OBSERVERS command or check the observer log file.

  • This command ignores any connections you have made to a specific configuration member using the CONNECT command. In other words, even if you have not connected to a specific member in the broker configuration, you can still start an observer by using the START OBSERVER IN BACKGROUND command.

  • If you have connected to a specific configuration member before issuing the START OBSERVER IN BACKGROUND command, then you can continue to use the connection after the control is returned.

  • If the observer_file parameter is not specified with the FILE IS parameter, then the observer searches the current working directory for the fsfo.dat file. If it is not found, then the observer creates a fsfo.dat file.

  • For the LOGIFLE IS clause, if a complete path, with file name, is provided, the file is stored in the specified path.

    If only a file name is provided and the DG_ADMIN environment variable is defined, the specified file is stored in the $DG_ADMIN/config_ConfigurationSimpleName/log directory. If the DG_ADMIN environment variable is not defined, the file is stored in the current working directory.

    If LOGFILE IS clause is omitted, the log file is stored in the $DG_ADMIN/config_ConfigurationSimpleName/log directory using the name observer_hostname.log. If the DG_ADMIN environment variable is not defined, the log file is stored as observer_hostname.log in the current working directory. ConfigurationSimpleName is the name of the broker configuration.

  • If a complete directory path and file name is specified with the FILE IS clause, the observer runtime data file is created in this directory. If a relative path and file name is specified, the file is created in the specified path under the current working directory.

    If only a file name is specified, the file is stored in the $DG_ADMIN/config_ConfigurationSimpleName/dat/ directory. If the DG_ADMIN environment variable is not defined, the file is stored in the current working directory. ConfigurationSimpleName, which is a configuration property, is the name of the broker configuration.

    If this clause is omitted, the file is stored as $DG_ADMIN/config_ConfigurationSimpleName/dat/FSFO_hostname.dat. If the DG_ADMIN environment variable is not defined, the file is stored in the current working directory as fsfo.dat.

  • The optional clause TRACE_LEVEL IS lets you control the amount of tracing done and written to the observer log file. The default value is USER, which limits the observer log contents to tracing information about fast-start failover, status changes of the primary and target standby database, and error/warning messages. Setting TRACE_LEVEL to SUPPORT increases the amount of tracing information to include lower-level information needed by Oracle Support Services.

  • The order of the optional clauses in the START OBSERVER IN BACKGROUND command is interchangeable.

Command Example

DGMGRL> START OBSERVER observer1 IN BACKGROUND 
FILE IS  /net/sales/dat/oracle/broker/fsfo.dat 
LOGFILE IS /net/sales/dat/oracle/broker/observer.log 
CONNECT IDENTIFIER IS sales_p;
Submitted command "START OBSERVER" using connect identifier "sales_p"