[tracker1]

You can scale past 15 nodes... it's just you'll want to tweak things and/or you won't get linear growth as you add more nodes. That doesn't mean you can't. Also, if you need more than that, Cassandra and other options are there, and you'll likely have to feel that pain regardless.

There are other ways to separate your data depending on use cases. It's just a rough guideline... You'll see similar issues beyond 10-20 servers in a local cluster in many of the NoSQL options.

RethinkDB also has much better consistency guarantees over Aerospike, not to mention being FLOSS under a more permissive license.