It's a specially designed networked filesystem as the storage layer of a hosted postgres DB. From what I've read it has some interesting properties like built-i

It's a specially designed networked filesystem as the storage layer of a hosted postgres DB. From what I've read it has some interesting properties like built-in redundancy, expandable storage, you can instantly spin up replicas and copy-on-write clones of the db, plus they claim 2x+ performance compared to vanilla postgres. From what I've gathered it's kind of similar to the Spanner db that google released a few months ago in that there's a pretty tight integration of the software with the hardware & network layer that they control, which is what makes some of these improvements possible. The other thing that I find promising, is RDS has always felt kind of awkward in terms of what's still vanilla postgres that you're on your own for and what AWS does for you. I haven't tried Aurora yet but it seems like it might feel more AWS-native (things like having better performance monitoring tools and using IAM roles to control the db users).