A lot of uses of Redis are suboptimal, but easy to set up and good enough. For example, "true" LRU is not always needed -- an approximation of LRU is sometimes

A lot of uses of Redis are suboptimal, but easy to set up and good enough. For example, "true" LRU is not always needed -- an approximation of LRU is sometimes sufficient. It's often not worth the time and money to do better. When you need to scale past what Redis can provide, you can move on to a different solution, as Github has done.