> In case of AZ with participant goes down, can I dynamically, promote > observers to participants? What are the pitfalls of this approach?
No, this won't work. There's no way to tell if an AZ is down or just unreachable. So if you have 3 in a unreachable AZ, and you "promote" 3 observers in the second AZ to participants, both can in theory make writes to the log and you'll end up with a split brain scenario. -Ivan
