Hi MillionQueries,
I'll have a go at answering:
1. Business Critical tier in Managed Instance comes with multiple secondaries, one of which is readable at a time (via ApplicationIntent=READONLY in the connect string). You don't need to do anything, it is set up behind the scenes for you and you can't really see the configuration either. General Purpose also has built-in HA but is not readable.
2. You don't need to do anything if the primary server goes down, a secondary will take over. You might have to reconnect though. It's fairly quick as the secondaries are already in place and ready.
3. The Business Critical tier gives resilience in one region in Azure so if that goes down you won't have access. You can set up a failover group to another region to protect against this and it will also provide read-only data in another region.
4. We've set up a failover group to another region for safety although hope never to use it!
- This reply was modified 3 years, 1 month ago by DNA_DBA.