Another under the radar Apache project I've found myself using is Apache KvRocks<p><a href="https://github.com/apache/kvrocks">https://github.com/apache/kvrocks</a><p>It's a Redis compatible database on top of RocksDB, so unlike Redis it uses the disk instead of RAM, but you can control how much data is cached in RAM, obviously Kvrocks will be slower than Redis for uncached data.<p>Useful in situations where you want a KV data store that isn't limited by your memory specs but is compatible with everything that speaks Redis.