Hi there, Squid is pegging CPU to 100% with "storeClientCopyEvent" and hit service time soar up to server seconds here. The following is what I see in cachemgr:events: OperationNext ExecutionWeightCallback Valid? storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent-0.019010 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes storeClientCopyEvent0.000000 seconds0yes MaintainSwapSpace0.980990 seconds1N/A idnsCheckQueue1.000000 seconds1N/A ipcache_purgelru5.457004 seconds1N/A wccp2HereIam5.464900 seconds1N/A fqdncache_purgelru5.754399 seconds1N/A storeDirClean10.767635 seconds1N/A statAvgTick59.831274 seconds1N/A peerClearRR110.539127 seconds0N/A peerClearRR279.341239 seconds0N/A User Cache Maintenance1610.136367 seconds1N/A storeDigestRebuildStart1730.225879 seconds1N/A storeDigestRewriteStart1732.267852 seconds1N/A peerRefreshDNS1957.777934 seconds1N/A peerDigestCheck2712.910515 seconds1yes So what does "storeClientCopyEvent" mean? Is it disk IO cause this problem? Regards, Liu