Re: [squid-users] Http Req/sec Once more

From: Joe Cooper <>
Date: Wed, 06 Feb 2002 16:31:41 -0600

khiz code wrote:

> Hi all and joe especially
> joe, i remember u giving me approximate statistics abt the capacity in terms of
> req/sec for a T1 line
> in myscenario i am connected to my upstream via a E1 (2.048 Mbps)
> my clients connect to me via leasedlines
> i have oversold my E1 capacity ( like all good ISPs ;-) abt 2 times to abt 5
> Mb/s
> so will the statistics change in terms of req/sec that the cache will receive
> sorry for being so dumb. once more ...
> one more thing
> commercial boxes like cisco, netcache etc give statisctics in terms of
> connections/sec that the box can handle
> my linux box has time-wait period of 60s
> tcp_max_syn_backlog = 8192
> local_port_range 1025 64000
> how can i calculate the number of simultaneous connections that this squid box
> can sustain for web traffic ..assuming that only squid runs on the box

Hehehe... How long is a piece of string, Khiz?

You haven't told us anything about your box. Here is what I sell for
one or two T1 links these days:

800MHz Celeron (can't get a 633 anymore, which also would be plenty of
1 x 7200 RPM 30GB disk

These boxes will sustain about 60-70 reqs/sec of real traffic without
sweating. Short (30 minute) bursts of loads of over 100 reqs/sec are
probably possible.

However, a client population suitable for a single T1 will never
generate that high of a sustained load. Our single T1 ISP clients are
seeing about 35 reqs/sec or less at their peak periods and their caches
aren't working very hard even when doing extra stuff like running
redirectors or acting as ICP peers (even our old 850 boxes which were
only 450MHz K6-2 with 192MB RAM). You can't make your users browse only
cache hits, so the speed of your cache isn't really your upper bound if
you have a T1.

Have you read my caching deployment guide at the Swell Technology site?
  It has some information about all of this stuff. I've also specified
all of our machines based on reqs/sec and bandwidth they will
handle--that ought to give you some rough ideas about what Squid can do
on given hardware if well tuned. (Some of this information is going
away soon, or being altered significantly, when our new website goes up
March 1st or thereabouts. So more up to date information and a lot more
of it will be on the site, but probably less specific for the kind of
info you are looking for--so enjoy it while it is available.)

Joe Cooper <>
Web Caching Appliances and Support
Received on Wed Feb 06 2002 - 15:31:44 MST

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