I'm not entirely sure what I'd search for so I figure I might as well ask here. When a key won't fit in redis, does redis remove the least active key(s) to make room? And is there a way to persist the removed keys to disk to possibly be retrieved at a later date? That way the most active keys remain in memory while the least active keys are still available.
I haven't actually experienced this, someone correct me if I am wrong: you can choose from different policies (LRU, TTL, random) to expire/remove keys, otherwise if you disable maxmemory it will start using the OS virtual memory and slow down.
Redis had a virtual-memory option like you describe at some point, but it was scraped due to poor performance and other issues.