I'd like to see more info on their customized Erlang/OTP mnesia . michalptaszek mentioned it in the comment: http://disq.us/p/1gltwfs

Sure, few words on customizations we've built into mnesia: - we integrated it with our eureka-based service discovery mechanism, so that it can automatically cluster with other servers that are spun up in a process of cluster bootstrap/resizing. Also relaxed constraints when merging 2 identical schemas of separate clusters (when table cookies don't match, but everything else matches we still want to merge and take a union of already existing data) - we've added a bunch of auto-merge code (heavily inspired by Ulf's wonderful https://github.com/uwiger/unsplit library) in case of network partitions - we've also added support for maintaining pools of processes for each table for dirty updates (as opposed of going through mnesia_tm for every single operation, including transactions as well as dirty_asyncs)

I'm 100% aware that these changes are RMS/Riot specific and won't work in many other situations (e.g. they violate certain transaction isolation properties).