We don't have MongoDB in production anymore BUT when we did... We had 27 instances (9 shards) 3 routers and 3 configs Main instances ran on c*.4xl machines wi

We don't have MongoDB in production anymore BUT when we did... We had 27 instances (9 shards) 3 routers and 3 configs Main instances ran on c*.4xl machines with 5,000-10,000iops disks. SSD wasn't nearly enough for us.