I've tried but with no luck. The number of close and write operations rose a lot, but with cache.log reporting queue congestion, squid became jammed, HIT service time soared up to several seconds and CPU usage was pegged to 100%... I have to manually restart squid to solve this problem. After restarting, squid can run pretty well for some time, with CPU usage not even exceed 50% under the same traffic load. Regards, Liu