- A switchover is a role reversal between the primary database and one of its standby databases. A switchover guarantees no data loss and is typically done for planned maintenance of the primary system. During a switchover, the primary database transitions to a standby role, and the standby database transitions to the primary role.<<http://docs.oracle.com/cd/E11882_01/server.112/e17023/sofo.htm>>
- A failover is done when the primary database (all instances of an Oracle RAC primary database) fails or has become unreachable and one of the standby databases is transitioned to take over the primary role. Failover may or may not result in data loss depending on the protection mode in effect at the time of the failover.
I have a question, Can i activate standby database, if primary crashes...?Yes
If so, how and what do we call it as, a switching or failover operation..?If primary crashes, if you make standby as primary then it is called failover.....................in failover you have to build standby again
Ok, I entered the command 'alter database activate standby database' in standby to make it a primary (edition of oracle as i mentioned in my Question)there might be dataloss, the above command is used for failover. you can use above command on standby only if primary is unavailable/crashed.
then, i don't know about the data loss occured or not. Is it a ' switchover' or 'failover'?
Performs a failover. The standby database must be mounted before it can be activated with this statement.<<http://docs.oracle.com/cd/E11882_01/server.112/e25608/sql_stmts.htm#i1005572>>
Note: Do not use the ALTER DATABASE ACTIVATE STANDBY DATABASE statement to failover because it causes data loss. Instead, use the following best practices: