I am switching my website cache system to use Memcached engine instead of using Files engine.
I know when I am using Files, the cached files were deleted when expiring.
It seems it's not the case with Memcached. Can you confirm this?
If it's the case, is there a way to avoid that?
Otherwise, I think the keys will be evicted at some point if they are not deleted, right?
Traditional Memcached does not actively delete expired values. Expired values are deleted when they are accessed or whenever they get evicted.
MemCachier's memcached implementation behaves in the same way.
There is also a Redis backed memcached service from RedisLabs but I am not familiar with its expiration behavior.