[squid-users] Re: Performance problems

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
>
>
Received on Mon Jul 17 2006 - 08:53:25 MDT