The fact that you’re thinking about this is great!
You’re right, there are two major types of fail-overs that you have to think about:
- Planned failover, when you can get to the original production system (at least for a short time)
- Unplanned failover, when you cannot get to it
Even when you’re doing a planned failover, you don’t have time to go in and script out settings and jobs and logins and all that stuff.
Timing is of the essence, so you need minimal manual actions.
And you really should have documentation so that whomever is on call can perform the failover, even if they aren’t you.
The short answer is, test, test, test. Test where it can’t hurt, and then test where it can. But do read/watch the whole thing.