[patsplat]

Ok then. Build an application heavily dependent on caching. Restart memcached in the middle a production workload. How long does it take to get out from under the dog pile?

EDIT: This started out a bit flippant. Wanted to make the point that antirez is not just handwaving.

For example one of the points without elaboration was 'there are “pure caching” use cases where persistence and replication are important'. Sometimes caching warming isn't feasible i.e. needing to restart the cache in the middle of a production workload. Using entirely volatile cache one can find extended downtime from the dog pile of requests waiting for the cache to warm up. Persistence can be an attractive form of insurance against this scenario.