About Starting and Stopping Components with Oracle Restart

About Starting and Stopping Components with Oracle Restart

Oracle Restart automatically restarts various Oracle components when required, and automatically stops Oracle components in an orderly fashion when you manually shut down your system. There may be times, however, when you want to manually start or stop individual Oracle components. Oracle Restart includes the Server Control (SRVCTL) utility that you use to manually start and stop Oracle Restart–managed components. When Oracle Restart is in use, Oracle strongly recommends that you use SRVCTL to manually start and stop components.

Oracle utilities such as SQL*Plus, the Listener Control utility (LSNRCTL), and ASMCMD are integrated with Oracle Restart. If you shut down the database with SQL*Plus, Oracle Restart does not interpret this as a database failure and does not attempt to restart the database. Similarly, if you shut down the Oracle ASM instance with SQL*Plus or ASMCMD, Oracle Restart does not attempt to restart it.

An important difference between starting a component with SRVCTL and starting it with SQL*Plus (or another utility) is the following:

* When you start a component with SRVCTL, any components on which this component depends are automatically started first, and in the proper order.

* When you start a component with SQL*Plus (or another utility), other components in the dependency chain are not automatically started; you must ensure that any components on which this component depends are started.

About Starting and Stopping Oracle Restart

The CRSCTL utility starts and stops Oracle Restart. You can also use the CRSCTL utility to enable or disable Oracle high availability services. Oracle Restart uses Oracle high availability services to start and stop automatically the components managed by Oracle Restart. For example, Oracle high availability services daemons automatically start databases, listeners, and Oracle ASM instances. When Oracle high availability services are disabled, none of the components managed by Oracle Restart are started when a node is rebooted.

Typically, you use the CRSCTL utility when you must stop all of the running Oracle software in an Oracle installation. For example, you might need to stop Oracle Restart when you are installing a patch or performing operating system maintenance. When the maintenance is complete, you use the CRSCTL utility to start Oracle Restart.

Oracle Restart Configuration

Oracle Restart maintains a list of all the Oracle components that it manages, and maintains configuration information for each component. All of this information is collectively known as theOracle Restart configuration. When Oracle Restart starts a component, it starts the component according to the configuration information for that component. For example, the Oracle Restart configuration includes the location of the server parameter file (SPFILE) for databases, and the TCP port to listen on for listeners.

If you install Oracle Restart and then create your database with Database Configuration Assistant (DBCA), DBCA automatically adds the database to the Oracle Restart configuration. When DBCA then starts the database, the required dependencies between the database and other components (for example disk groups in which the database stores data) are established, and Oracle Restart begins to manage the database.

You can manually add and remove components from the Oracle Restart configuration with SRVCTL commands. For example, if you install Oracle Restart onto a host on which a database is already running, you can use SRVCTL to add that database to the Oracle Restart configuration. When you manually add a component to the Oracle Restart configuration and then start it with SRVCTL, Oracle Restart begins to manage the component, restarting it when required.