One of the biggest benefits from being acquired by Facebook was working with the RocksDB team to come up with MongoDB +RocksDB, but this was also happening around the time when Parse was starting to wind down.
Being the only company running this new storage engine freaked us the fuck out. So we tried to blog and give talks as much as possible to get other folks interested and willing to test it out.
Parse now running MongoDB on RocksDB: http://blog.parse.com/announcements/mongodb-rocksdb-parse/
Strata: Open Source Library for Efficient MongoDB Backup: http://blog.parse.com/learn/engineering/strata-open-source-l...
MongoDB + RocksDB: Writing so Fast it Makes Your Head Spin: http://blog.parse.com/learn/engineering/mongodb-rocksdb-writ...
MongoDB + RocksDB: Benchmark Setup & Compression: http://blog.parse.com/learn/engineering/mongodb-rocksdb-benc...