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Message-ID: <4430ECB2.7040308@weboperations.com>
Date: Mon, 03 Apr 2006 12:36:50 +0300
From: Tp <tp@weboperations.com>
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To: Tomcat Users List <users@tomcat.apache.org>
Subject: Re: Maximum number of simultaneous HTTP Requests / Performance
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 <6d959d480604030214h1cad6504q8e35132bb851dc5f@mail.gmail.com>
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Remy Maucherat schrieb:
> On 4/3/06, Tp <tp@weboperations.com> wrote:
> 
>>Hi,
>>
>>we have to develop a high performance chat based only on HTML and HTTP
>>only for a television company. The biggest issue is performance. The
>>chat's output window requires one open HTTP connection per client. This
>>means, that when you have 3000 people following the chat that the server
>>has to be able to handle 3000 simultaneous ie. open HTTP connections.
>>
>>I have read some old benchmark tests. In those Tomcat does not get a
>>very good rating compared to other servers like JRun, BEA and others,
>>since it does not use NIO or some native methods. I guess I could try
>>just to open 3000 threads on my machine which write some output and see
>>how it's doing but I guess that does not really tell me anything reliable.
>>
>>So I was wondering if anybody can really tell me what Tomcat's (5.5)
>>limit is on this? How many simultaneous HTTP connections can Tomcat
>>handle and still respond in such a way, that the application stays
>>useable. I assume that the machine runs on a Pentium 4 3.2 Ghz with 1 GB
>>of RAM under linux and that all the file descriptor limits are set to
>>the maximum.
>>
>>The second question I have is, that lets assume the limit of a single
>>tomcat instance is at 2000 connections, how could I use a cluster and
>>loadbalancer to increase the total amount of simultaneous HTTP
>>connections of the "Applicaiton" and this really possible? Does anybody
>>in here have pratical experience for a live production system, which is
>>in use and handles many HTTP connections?
> 
> 
> Neither the HTTP protocol (of course, since you control the network
> environment, you cannot run into trouble with proxies), nor the
> Servlet API have been designed to be used to do biderectional
> asynchronous communication and forever running service methods (what
> you're actually doing in that case is running your own protocol on top
> of HTTP), and in that case, there's no solution except using a large
> amount of threads. 

Yes, you are right on the point! However, the Servlet API could have 
been developed in such a way that it only uses a single thread for 
several connections. I have written a java http proxy, which handles 
multiple open http connections using just a single thread. And it 
performs really well.

I don't know if you're aware of it, but the SIP
> protocol (and the associated SIP Servlets specification) has been
> designed for exactly this sort of usage, and using it or a similar
> custom protocol may be a lot better than trying to hack stuff.
> 

No, never heard about it. Sounds interesting. But I don't think it will 
  solve my problem handling a large number of open http connections 
simultanesously, or will it?

> OTOH, OSes like recent Linux versions have no problem with lots of
> threads (like 5000) as long as threre are enough resources, so you
> could test that solution and see how it works.
> 

Yes, but maybe somebody else already has and can tell me;) By the way 
I'm using JBoss for all other projects, promoted it in my former company 
and I think it's a great product! What do you think about glassfish and 
geronimo?


yours,
Tim
> --
> xxxxxxxxxxxxxxxxxxxxxxxxx
> R�my Maucherat
> Developer & Consultant
> JBoss Inc
> xxxxxxxxxxxxxxxxxxxxxxxxx
> 
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