This article is not about how bad MongoDB is, you can google it if you search for arguments. I heard the MongoDB had issues with failover, but I cannot confirm it from my experience. I heard bad opinions about this database engine, but it has good and bad sides. In my opinion, it is a good tool for coders.
What is Redis and what is Memcached? Why use Redis and when Memcached? Way we can call Redis a NoSQL database? Today I want to present my conclusions about which cache engine to use? Redis versus Memcached.