Have you looked into using ets storage instead of bitcask storage? Millions of keys at ~12bytes value would fit just fine in memory without the bitcask overhead

Have you looked into using ets storage instead of bitcask storage? Millions of keys at ~12bytes value would fit just fine in memory without the bitcask overhead and as long as your N value is > 1 you shouldn't have to worry about data loss unless your whole cluster loses power.