Installing Oracle Parallel Server has an impact on how database files are used. Some files—for example, the datafiles—are shared among all instances. Other files are not. This section discusses each type of file in terms of how it is used in an OPS configuration.
In an OPS configuration, you need to be concerned about three types of initialization parameters:
Some parameters, such as GC_FILES_TO_LOCK, must be the identical across all instances. These are known as global constant parameters.
Certain other parameters, such as DB_BLOCK_BUFFERS, do not need to be the same for each instance.
Still other parameters, such as ROLLBACK_SEGMENTS, actually must be different for each instance.
Because the parameters for each instance in an OPS configuration won’t all match, each instance must have its own initialization parameter file (INIT.ORA). When you change a parameter in an OPS configuration, make sure to consider whether that parameter is a global constant parameter. If it is a global constant parameter and you change it, you must remember to change it in all of the parameter files. Chapter 7, goes into detail on the subject of OPS initialization parameters and the files used to manage them.
Place all common initialization parameters in one common parameter file. Then, use the IFILE directive in each instance-specific parameter file to include this common file. This eases the administrative burden of keeping the global common parameters ...