What really differentiated it was the fact that multi-key transactions allowed for you to reasonably build any number of logical data models on top of it in a l

What really differentiated it was the fact that multi-key transactions allowed for you to reasonably build any number of logical data models on top of it in a linearly scalable way. It was all built to an extremely high degree of polish with an extremely good testing and simulation harness and a high degree of predictability in performance. It was basically Spanner for the rest of us, without atomic clocks (and they also shipped an F1, their SQL layer on top). As others have mentioned, the closest cousin at the moment is probably cockroach, but it relies on wall clocks which will probably lead to problems in certain cases, but gets an easier way to scale writes. Here's the architecture diagram for FDB, it's pretty fun to read: https://foundationdb.com/files/Architecture.pdf https://foundationdb.com/files/Architecture.pdf