On 10/24/2013 07:43 AM, Omid Kosari wrote: > "digest_generation off" temporary solved problem but needs restart . I have > tested with reload before . Sounds like you have detected the source of the blocking Squid problem and confirmed it! The fact that digest generation makes your Squid unresponsive is essentially a Squid bug, but you might be able to help Squid by adjusting its configuration. If you want to try it, I suggest re-enabling digest generation and setting digest_rebuild_chunk_percentage to 1. If that works around your problem, great. Unfortunately, I suspect Squid may still be unresponsive during digest generation time because of how regeneration steps are scheduled and/or because of an old bug in the low-level scheduling code of "heavy" events. However, using the minimum digest_rebuild_chunk_percentage value (1) is still worth trying. > But i could not use digest benefits anymore . Is there big penalty if both > caches are in same gigabit switch ? The digest optimization can be significant if the two Squids share a lot of popular content _and_ it takes a long time for each Squid to get that content from the internet during a miss. HTH, Alex.