How does Oracle9i make sure that the database is available to users at all times?

Question

What will be an ideal response?

Answer 1

The database must be readily available to the users at all times. There are safety measures
considered at the planning phase, configuration phase, and implementation phase for the
availability issue. The three configurations are replication, hot standby database, and parallel
server. The Replication method uses separate databases by duplicating the entire
implementation of the database on multiple computer systems, where all updates are
performed on all database implementations. The operations can still continue if one of the
databases crashes. The hot standby database method uses only one database at a time. The
other standby copy is in recover mode at all times. The redo log files are used to recover the
standby copy. If the primary copy fails, the standby copy is recovered completely and is
brought up as the primary database. In an Oracle parallel server configuration, multiple
computer systems are used with parallel processing capability to share a common
database. In the event of a computer system failure, the operations still continue as long as
the shared database is available.