500 concurrent connections! was: Re: problem with load balancing..solved.

[John Econopouly <jo...@hotmail.com>]

That's funny, my experience has been the opposite.  I've been testing a 
system that uses blocking HTTP connections so that I can push data back to 
clients (using tomcat 3.1, RedHat 6.1, various jdks on a P6 w/ 1000MB).  So 
I need alot of threads (one (or two?) per connection, and I'm trying to 
reach 1000 concurrent TCP connections).
Based on sources like the Volano report, I thought Blackdown 1.2.2rc4 would 
be the best choice.  They manage 4000 concurrent connections using that jdk. 
  But I could only manage 250.  At first I assumed the limitation was 
tomcat.  But then I noticed that I couldn't even run more than 500 threads 
at once with Blackdown at all (a simple dummy program: spawn 600 threads 
each of which prints i++ every second, and then sleeps - the last hundred 
threads or so keep printing zero), using green _or_ native.
I switched to the sun jdk, and the good news is I can now support 500 
concurrent connections, using tomcat!  It was also about 4x faster.  (The 
bad news is that it seems to crap out after about 50000 cumulative 
connections of this kind, but that's still a big improvement).  I also tried 
the new ibm 1.3 jdk, but results were similar to the blackdown jdk.  I don't 
want to draw too many conclusions until I'm done testing... but I think it's 
good advice to always try out a few jvms.

>From: <yh...@mimic.onesourcecorp.com>
>Hi guys,
>i solved my load balancing lockup problem. its not with tomcat 3.2...its
>with the new sun jdk 1.2 that i was using instead of blackdown. do *NOT*
>use the sun JDK under heavy loads or load balancing. it locks up easily.

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Re: 500 concurrent connections! was: Re: problem with load balancing..solved.

[yh...@mimic.onesourcecorp.com]

On Thu, 6 Jul 2000, John Econopouly wrote:

> 
> That's funny, my experience has been the opposite.  I've been testing a 
> system that uses blocking HTTP connections so that I can push data back to 
> clients (using tomcat 3.1, RedHat 6.1, various jdks on a P6 w/ 1000MB).  So 
> I need alot of threads (one (or two?) per connection, and I'm trying to 
> reach 1000 concurrent TCP connections).
> Based on sources like the Volano report, I thought Blackdown 1.2.2rc4 would 
> be the best choice.  They manage 4000 concurrent connections using that jdk. 
>   But I could only manage 250.  At first I assumed the limitation was 
> tomcat.  But then I noticed that I couldn't even run more than 500 threads 
> at once with Blackdown at all (a simple dummy program: spawn 600 threads 
> each of which prints i++ every second, and then sleeps - the last hundred 
> threads or so keep printing zero), using green _or_ native.
> I switched to the sun jdk, and the good news is I can now support 500 
> concurrent connections, using tomcat!  It was also about 4x faster.  (The 
> bad news is that it seems to crap out after about 50000 cumulative 
> connections of this kind, but that's still a big improvement).  I also tried 
> the new ibm 1.3 jdk, but results were similar to the blackdown jdk.  I don't 
> want to draw too many conclusions until I'm done testing... but I think it's 
> good advice to always try out a few jvms.
> 
> >From: <yh...@mimic.onesourcecorp.com>
> >Hi guys,
> >i solved my load balancing lockup problem. its not with tomcat 3.2...its
> >with the new sun jdk 1.2 that i was using instead of blackdown. do *NOT*
> >use the sun JDK under heavy loads or load balancing. it locks up easily.
> 

uuh...did you try load balancing or regular non load balanced ? suns JDK
works fine when its non load balanced but with load balancing it dies
easily under heavy loads. advantage of load balancing is that you dont
need a monster box to service 50K requests...a cluster of load balanced
boxes can be made to act like one (if you have single system image
capability in your session handlers like i do).
ideally, you would be running multiple JVMs with 125 users/JVM at the max. 
-Ys-
yhs@mimic.onesourcecorp.com