> in-memory and disk-backed, in-memory KV stores, which haven't really gone away even with the introduction of NVMe storage If we're talking caches and Redis,

> in-memory and disk-backed, in-memory KV stores, which haven't really gone away even with the introduction of NVMe storage If we're talking caches and Redis, one thought about why they haven't gone away-- In practice I think sharing is part of what keeps them network services, not only access to a cluster's RAM. As a dev you reach for something shared and 'shaped' like a cache, and the in-RAM aspect may be vestigial but still comes with the package. We use Redis when e.g. tracking stats on active client IPs to see which are up to shenanigans, a maybe common use where you want cluster-wide stats. When caching, we may still want one DB query per expiry period app-wide, not one per webserver. We would probably be fine 'caching' some stuff in the DB; Django's cache package has supported it for a while! I'm sure one of the disk-using successors of an in-RAM store could hit perf targets (DragonflyDB looks cool!). Just not a priority to change stuff that's working. (Corollary: I bet some folks unhappy with their Redis RAM needs are more than happy to try Dragonfly.)