My cached objects will expire after 10 minutes. Cache-Control:max-age=600 I don't know why there are so many disk writes and there are so many objects on disk. In addtion, Disk hits as % of hit requests: 5min: 1.6%, 60min: 1.9% is very low. Can I increase the cache_mem？ or not use disk cache at all? 2011/8/18 Łukasz Makowski <lukasz.makowski@xxxxxxxxx>: > W dniu 2011-08-18 08:19, Chen Bangzhong pisze: >> >> I have some Dell 1950 servers dedicated to squid in my production >> environment. Each with 16GB RAM and 300G disk >> As the website traffic grows, the load of squid becomes high at high >> traffic time. Average load is higher than 10. >> >> Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz >> avgqu-sz await svctm %util >> sda 0.00 0.01 0.06 0.13 1.23 1.45 28.87 >> 0.00 4.13 2.19 0.04 >> sda1 0.00 0.01 0.06 0.11 1.23 1.45 31.59 >> 0.00 4.52 2.40 0.04 >> sdb 0.07 0.07 0.01 0.01 0.33 0.32 59.88 >> 0.00 19.75 15.74 0.03 >> sdc 0.00 2.08 9.13 104.44 81.30 1066.74 >> 20.22 0.50 11.95 1.73 19.63 >> >> avg-cpu: %user %nice %system %iowait %steal %idle >> 3.50 0.00 3.75 24.34 0.00 68.41 >> >> Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz >> avgqu-sz await svctm %util >> sda 0.00 0.00 0.50 0.00 2.00 0.00 8.00 >> 0.04 70.00 70.00 3.50 >> sda1 0.00 0.00 0.50 0.00 2.00 0.00 8.00 >> 0.04 70.00 70.00 3.50 >> sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 >> 0.00 0.00 0.00 0.00 >> sdc 0.00 0.00 21.50 186.00 204.00 3106.25 >> 31.91 17.76 100.55 2.63 54.65 >> >> Here is the squidclient mgr:info output >> >> Squid Object Cache: Version 3.1.12 >> Start Time: Sun, 14 Aug 2011 19:39:15 GMT >> Current Time: Thu, 18 Aug 2011 04:41:20 GMT >> Connection information for squid: >> Number of clients accessing cache: 77651 >> Number of HTTP requests received: 40449309 >> Number of ICP messages received: 0 >> Number of ICP messages sent: 0 >> Number of queued ICP replies: 0 >> Number of HTCP messages received: 0 >> Number of HTCP messages sent: 0 >> Request failure ratio: 0.00 >> Average HTTP requests per minute since start: 8319.3 >> Average ICP messages per minute since start: 0.0 >> Select loop called: 476454933 times, 0.612 ms avg >> Cache information for squid: >> Hits as % of all requests: 5min: 30.7%, 60min: 32.1% >> Hits as % of bytes sent: 5min: 40.5%, 60min: 43.2% >> Memory hits as % of hit requests: 5min: 88.3%, 60min: 88.8% >> Disk hits as % of hit requests: 5min: 1.6%, 60min: 1.9% >> Storage Swap size: 120792244 KB >> Storage Swap capacity: 90.0% used, 10.0% free >> Storage Mem size: 5191632 KB >> Storage Mem capacity: 100.0% used, 0.0% free >> Mean Object Size: 20.61 KB >> Requests given to unlinkd: 0 >> Median Service Times (seconds) 5 min 60 min: >> HTTP Requests (All): 0.00865 0.00865 >> Cache Misses: 0.01035 0.01035 >> Cache Hits: 0.00000 0.00000 >> Near Hits: 0.00091 0.00091 >> Not-Modified Replies: 0.00000 0.00000 >> DNS Lookups: 0.00000 0.00000 >> ICP Queries: 0.00000 0.00000 >> Resource usage for squid: >> UP Time: 291725.519 seconds >> CPU Time: 37204.391 seconds >> CPU Usage: 12.75% >> CPU Usage, 5 minute avg: 19.42% >> CPU Usage, 60 minute avg: 18.20% >> Process Data Segment Size via sbrk(): 1012440 KB >> Maximum Resident Size: 28552368 KB >> Page faults with physical i/o: 2957 >> Memory usage for squid via mallinfo(): >> Total space in arena: -1265560 KB >> Ordinary blocks: -1308538 KB 264611 blks >> Small blocks: 0 KB 0 blks >> Holding blocks: 20708 KB 9 blks >> Free Small blocks: 0 KB >> Free Ordinary blocks: 42978 KB >> Total in use: -1287830 KB 103% >> Total free: 42978 KB -3% >> Total size: -1244852 KB >> Memory accounted for: >> Total accounted: -1781767 KB 143% >> memPool accounted: 6606841 KB -531% >> memPool unaccounted: -7851693 KB 0% >> memPoolAlloc calls: 10008474163 >> memPoolFree calls: 10065124847 >> File descriptor usage for squid: >> Maximum number of file descriptors: 20480 >> Largest file desc currently in use: 4828 >> Number of file desc currently in use: 4703 >> Files queued for open: 178 >> Available number of file descriptors: 15599 >> Reserved number of file descriptors: 100 >> Store Disk files open: 22 >> Internal Data Structures: >> 5860834 StoreEntries >> 256880 StoreEntries with MemObjects >> 256646 Hot Object Cache Items >> 5860661 on-disk objects >> >> related parameters >> >> cache_mem 5120 MB >> maximum_object_size 51200 KB >> maximum_object_size_in_memory 1024 KB >> >> log_icp_queries off >> cache_swap_low 90 >> cache_swap_high 95 >> hosts_file /etc/squid/hosts >> cache_dir aufs /export/squid/cache 131072 32 256 >> >> Is there any idea I can tune my squid performance? >> > Hi, > > First of all, I would try to change cache_dir acces method from aufs to > diskd and experiment with Q1 and Q2 parameters. > > Regards, > > LM > >
