Appendix: Using the SPFILE in an Oracle Cluster

Oracle versions prior to Oracle9i used an initialization file initSID.ora, a text file, to start database instances. Changes applied to instance parameters during a database session were not saved to the file; you had to manually apply them to the initialization file.

Oracle9i introduced the SPFILE, which is a binary file stored on the database server. With this feature, changes to the instance parameters can be set to be persistent across all startup and shutdown procedures.