Re: [squid-users] retrieving 1 file with 50 concurrent connections from memory cache in reverse proxy is really slow?

ab is good for some kinds of benchmarking, but one of the problems
with it is that it doesn't give you enough information to determine if
the bottleneck is in the server, the network or the client.

Take a look at httperf...

Cheers,

On 15/05/2008, at 8:15 AM, wheres theph wrote:

> I set up a squid as a reverse proxy that round robins to 2
> webservers (one is which is the same machine where squid is), and it
> appears that things work fine as a single user browsing casually.
> However, doing an apachebench request with 50 concurrent users to
> the same url times out the apachebench request:
>
> ***********************
> # ab -c 50 -n 250 -H "Accept-Encoding: gzip,deflate"
> http://www.domain.com/images/20k.gif
> This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $>
> apache-2.0
> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
> Copyright 2006 The Apache Software Foundation, http://www.apache.org/
>
> Benchmarking domain.com (be patient)
> Completed 100 requests
> Completed 200 requests
> apr_poll: The timeout specified has expired (70007)
> Total of 238 requests completed
>
> ***********************
>
> On the first access of the gif file, the access.log shows the TCP_MISS
> as expected. Subsequent accesses show the TCP_MEM_HIT as expected
> also.
>
> No errors show up in squid.out. Any ideas on why serving a static
> image
> from memory is so slow that ApacheBench times out?
>
>
> My round robin setup is pretty standard I think:
> *************
> http_port 12.34.56.1:80 vhost defaultsite=www.domain.com
> http_port 3128
> cache_peer 12.34.56.2 parent 80 0 no-query originserver round-robin
> cache_peer 127.0.0.1 parent 80 0 no-query originserver round-robin
>
> cache_dir null /tmp
>
> url_rewrite_host_header off
>
> acl our_sites www.domain.com
> http_access allow our_sites
>
> maximum_object_size_in_memory 1024 KB
> *************
>
> I am using CentOS 5, squid v 2.6.STABLE6-5.el5_1.
>
>

--
Mark Nottingham       mnot_at_yahoo-inc.com