Switchover - Role reversal between primary and standby databases. Old primary is now a standby. Used for hardware upgrades, OS upgrades, etc. · Failover - Primary is down with little hope of quick recovery (ie. hardware failure on primary machine).Once failover has been initiated , the old primary database is no longer useful. STEPS OF SWITCHOVER On primary database: Sql> select switchover_status from v$database ; Initiate switchover on primary database : Sql> alter database commit to switchover to physical standby; After the above statement completes the old primary is now a standby database. While still on old primary shutdown database and restart as standby: Sql>shu immediate; Sql>startup nomount; Sql>alter database mount standby database; On the old standby system (new primary) Sql> select switchover_status from v$database; On new primary complete switchover then restart database: Sql>alter database commit to switchover to primary; Sql>shu immediate; Sql>startup; On new standby start managed recovery: Sql>alter database recover managed standby database disconnect from session; On new primary begin redo transport: Sql>alter system archive log current; Switchover complete. STEPS OF FAILOVER Manually register any redo logs with the standby that are available and that have not been applied. If using standby redo logs, initiate failover with: Sql> alter database managed standby database finish; If not using standby redo logs: Sql> Alter database recover managed standby database finish skip standby logfile; Convert the Physical Standby to Primary (modify pfile before restart): Initialization Parameters: ... log_archive_dest_1='location=use_db_recovery_file_dest valid_for=(all_logfiles,all_roles) db_unique_name=prods' log_archive_dest_2='service=prod valid_for=(online_logfiles,primary_role) db_unique_name=prod' log_archive_dest_state_1='ENABLE' log_archive_dest_state_2='DEFER' fal_server='prod','prods' fal_client='prods' ... Sql>alter database commit to switchover to primary; Sql>shu immediate; Sql>startup; Failover complete.