I'm currently setting up AlwaysOn SQL Server cluster. We have 3 DR sites: London, Amsterdam, and Amazon, with London and Amsterdam synchronous, and Amazon asynchronous.
I have a couple of questions:
- I want to use read-only routing and the London to Amsterdam network latency is 8ms. Is that good for read-only routing or should I make another synchronous node in London, which is going to be the primary replica, and change Amsterdam to asynchronous?
- Does the secondary replica have to have the same amount of memory as the primary?