Forgot one additional piece of information: Squid version used is 2.5.13. But we've been having these problems with 2.5.7, 2.5.10 and 2.5.12 too. Joost de Heer wrote: > Hello, > > For a while, we've been having performance problems on one of our proxies. > So far it looks like the machine is responding horridly when memory is > freed. > > Here's some sample output from vmstat: > > 20060717-120000 2 3 0 18332 190544 1013220 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120100 2 0 0 20744 191040 1014308 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120200 2 0 0 20620 191576 1013444 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120300 2 0 0 20828 192012 1012816 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120400 1 0 0 29832 192392 1002868 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120500 1 0 0 58108 192524 971760 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120600 2 0 0 69172 192784 965056 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120700 2 0 0 45644 193200 988184 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120800 2 0 0 24668 193604 1008776 1 1 0 3 > 0 0 2 2 1 1 > 20060717-120900 2 0 0 21576 194048 1011436 1 1 0 3 > 0 0 2 2 1 1 > 20060717-121001 4 0 0 18056 194400 1010904 1 1 0 3 > 0 0 2 2 1 1 > 20060717-121100 2 0 0 18652 194904 1013504 1 1 0 3 > 0 0 2 2 1 1 > > Between 12:04 and 12:07, the machine was responding very poorly. > > Output of 'free': > > total used free shared buffers cached > Mem: 2055448 2034576 20872 0 202756 1002868 > -/+ buffers/cache: 828952 1226496 > Swap: 8388600 0 8388600 > > Specs of the machine: > > Dual processor Intel(R) Xeon(TM) CPU 3.20GHz, 2 GB memory, machine has 3 > HD's: 2x72.8GB mirror for OS/software/logs and 1x72.8G single disk for > cache. > > OS: Linux kslh086 2.4.21-37.ELsmp #1 SMP Wed Sep 7 13:28:55 EDT 2005 i686 > i686 i386 GNU/Linux (upgrade to 2.6 is unfortunately not possible) > > Disks are all ext3. > > Relevant squid.conf lines: > > cache_replacement_policy heap GDSF > memory_replacement_policy heap GDSF > memory_pools off > cache_swap_low 90 > cache_swap_high 95 > maximum_object_size 64 KB > maximum_object_size_in_memory 8 KB > > Apart from squid, Apache httpd 2.2.2 and BIND 9.3.2 (as a caching DNS > server) are running on this machine. > > Relevant Apache config: > > MinSpareServers 5 > MaxSpareServers 5 > StartServers 5 > MaxRequestsPerChild 0 > MaxClients 5 > > I've already minimised the cache (it's only 1G large now) to see if the > problem was too much disk access, but no luck. > > Normal cache usage is about 300-350 req/s, throughput is about 2.5MB/s, > and usually there are about 2000-2500 fd's open (proxy is configured to > run with 8192 available fd's, we can't lower this as the peak usage seems > to be about 6000 fds) > > Anyone has any ideas what might cause this? Directions to search for? > > Joost > >
