There's nothing in that post about your data centers, just your "stack". Of what does your service stack comprise? Why did you not opt for 2N? Do you co-locat

There's nothing in that post about your data centers, just your "stack". Of what does your service stack comprise? Why did you not opt for 2N? Do you co-locate? What tier is the DC? If you colo, especially <= T3, your colo company has likely cut corners somewhere and that you don't know about some of the weaknesses in their infrastructure.