Squid limitation ?

From: Kabak Jean-Francois <kabak@dont-contact.us>
Date: Tue, 03 Feb 1998 15:19:39 +0000


I'm using squid on different platform and have limitation problem with the
number of user connected:

My test consist of choosing a platform configuration, testing it with 0 to
500 peoples and estimating a good response time.

I use the "netstat -an" to get the number of user connected to my proxy and
wget (webget) to determinated download times (object in or not in cache).

The problem occured after the 100 users connection. When you ask for an
object in memory (you ask twice an object, the first time to put it on a
memory and the next time to calculate response time) you have to wait 5 to
30 seconds before your second request start to be treated.

Different platform configuration I tryied :
- I made some snoop between my PC and the proxy to isolate some networks pb
(no pb!) and calculate the amount of time between
the arrival of my request on the proxy and the response of squid to my PC
- increasing the amount of memory (128Mb => 190Mb) to limit swapping and
grow cache memory
- changing the HDD configuration (1x4Gb=>2x2Gb) to reduce iowait to my proxy
- I upgraded my CPU from Pentium100 to Pentium pro 200
- I stopped ICP configuration between machines (sibling and multicast) to
reduce the number of object treated by the proxy) (5proxy's)
- I tryied this tests during iddle and rush internet hours
- I tryied to modify (one at time) squid.conf parameters
- I tryied this on a SparcStation 20, 75mhz bi-processor, 256Mb memory, ODS
8gb Hdd

I tryied to compare squid performances to MS-Proxy 2.0 on a NT4.0 system. I
calculated the number of
users with a shell perl script (perl32 for NT) and the "netstat -an" NT
command (not the same than solaris).
It seems that NT4.0 with proxy server 2.0 accept few more people (110/140)
for the machine and response time.
MS-Proxy 2.0 also give the number of connected people but this statistic
seems strongly incorrect.

Here is my conclusion :
whatever the configuration may be, I always get limited to 100/130 users
with squid (according to CPU,MEM and HDD config) !!!
After this limit, response time is too long to satisfy users

Can someone tell me more about this results ?

More informations:
-Intel Pentium 100/120/133/pro200 - SUN SS20 bi-pro
128Mb/190Mb EDO memory - 256 SIMM 32 Mb
1Gb Hdd(system) QUANTUM+ 4Gb cache (1x4Gb or 2x2Gb) QUANTUM- 8Gb with ODS
Fast/Wide SCSI (10/20Mb) 2940 adaptec card
10/100Mb 3com network interface
Solaris 2.6 x86 - Solaris 2.5.1
Squid 1.1.11 to Squid 1.1.17
Compilation with GCC 2.7.2

  Jean-Francois Kabak kabak@infonie.fr
  Ingénieur système et réseau

  Infonie http://www.infonie.com
  16 rue Hoche
  92906 Paris la Défense
Received on Tue Feb 03 1998 - 06:30:21 MST

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