If I split my cache like this: cache_dir aufs /usr/local/squid/small_obj 1700 16 256 max-size=800000 cache_dir aufs /usr/local/squid/big_obj 200 16 256 Presumably nothing bigger than max-size will end-up in the first cache, but how often will the smaller objects end-up in the second cache? Assuming that both cache-directories have filled.