Ehhhh, doesn't align with my experience. I think FDB is actually really poorly tested. When I was evaluating it for replacement of the metadata key-value store at a major, public web services company we found that injecting faults into virtual NVMe devices on individual replicas would cause corrupt results returned to clients. We also found that it would just crash-loop on Linux systems with huge pages, because although someone from the project had written a huge-page-aware C++ allocator "for performance", evidently nobody had ever actually tried to use it, including the author.

It's also really, really weird that their non-scalable architecture hits a brick wall at 25 machines. Ignoring the correctness flaws, it only works if you can either design around that limit by sharding, and never off cross-shard transactions, or if you can assure yourself that your use case will never outgrow half a rack of equipment.