I just noticed that all of our EC2 instances are in zone us-west-2b, but our Multi-AZ RDS instance is in us-west-2a. Performance-wise everything seems to be okay, and it will be a hassle to "move" the instances to one place since you have to stop and re-create them all. However if either of the two zones goes down when we will have some downtime; if everything is in one zone then at least we have a higher chance of not being in the zone that has downtime... Is this something worth fixing, or am I over-thinking it? (I was about to purchase some EC2 Reserved Instances, which are tied to specific AZs, so I wanted to make sure before going through with it) Thanks!