My last team decided to hand manage a Memcached cluster because it cost half as much as an unmanaged service versus AWS’s alternative. Don’t know how much we really saved versus opportunity cost on dev time though. But it’s close to negative.
Because it was mostly fine at first, but later we had some close calls when there were changes that needed to be made on the servers. By the time we managed to mess up our hand managed incremental restart process, we had several layers of cache and so accidentally wiping one didn’t murder our backend, but did throw enough alerts to cause a P2. And because we were doing manual bucketing of caches instead of consistent hashing we hit the OOMKiller a couple times while dialing in.
But at this point it was difficult to move back to managed.
This feels closest to digital ocean’s business model.