Is it possible to have a 64bit Standby database from a 32bit Primary database?
Yes this is possible if you install 32bit Oracle on the 64bit server.
The OS does not need to be the same bit level between primary and standby server, but the Oracle version does.
For more information on the system requirement for both Standby v7 and v8, please see below:
Standby v7 System Requirements Link
Standby v8 System Requirements Link
Arjen Visser June 14, 2013 22:46