Oracle Instance Management

An Oracle database server consists of an Oracle database and Oracle instance. An Oracle instance is made up of memory buffers known as the System Global Area (SGA) and background process that handle much of the behind-the-scenes work involved in running an instance.
The instance is idle(nonexistent) until it is started. When the instance is started, an initialization parameter file is read and the instance is configured according to instructions contained within the parameter file.
After the instance is started and the database is opened, user can access the database.

Optimal Flexible Architecture (OFA)

OFA is a methode for configuring the Oracle database and other database. OFA takes the advantage of the OS and disk subsystems capabilities to create an easy-to-administer configuration that allows maximum flexibilitiy for growing and high-performance database. the methodes described here are basics of OFA.

OFA is designed to:

• Organize large amounts of complicated software and data on disk, to avoid device bottleneck and poor performance.
• Facilitate routine administrative tasks such as software and data backup, which are often vulnerrable to data corruption.
• facilitate switching between multiple Oracle databases.
• Adequately manage and administer database growth.
• Help eliminate fragmentation of free space in the data dictionary, isolate other fragmentation, and minimize resource contention.