Starting up an OPS database is quite different from starting up a standalone database.
You can start an Oracle Parallel Server instance in either exclusive mode or shared mode. In exclusive mode, only one instance can mount and open the database. In shared mode, multiple instances can mount and open the database simultaneously. The initialization parameter PARALLEL_SERVER determines which mode is used when a database is started. Shared mode is the normal operating mode for an OPS database. Exclusive mode is required for certain administrative tasks such as switching ARCHIVELOG mode on or off. (See Section 7.4.1 later in this chapter.)
If you are using Oracle8 (not Oracle8i ), you must start Group Membership Services (GMS) before you can start an OPS instance. This is true regardless of whether you are starting the instance in shared or exclusive mode. The next few sections show you how to start up an OPS database in exclusive mode and shared mode and how to start GMS.
To start up an instance in exclusive mode, you must choose an instance to use, and you must set the initialization parameter PARALLEL_SERVER to FALSE for that instance. Only one instance can open a database in exclusive mode. In order for that to happen, you must first shut down all the instances that normally open the database in shared mode.
While exclusive mode implies that only one instance has the database open, the reverse is not necessarily ...