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From Kirk <kirk.pepperd...@gmail.com>
Subject Re: determining ramp-up period
Date Thu, 23 Jun 2011 10:06:46 GMT
One has to really be careful with JMeter's threading model. It has the potential to act as
the bottleneck in your load test. I've seen a few teams chasing all kinds of things in the
app server when they really needed to be looking at what was coming behind them. IMHO, a thread
per user is an easy model to grasp but is much easier to set yourself up for failure. Case
in point, and earlier suggestion that if the response times are greater than the desired rate
of arrival at the server, the throughput will drop 'cos JMeter will simply not have enough
threads to trigger the request. Hence, the bottleneck in the system will be JMeter. While
some might argue that this is sill ok (and in a number of cases it's not harmful), an event
based model would be much more scalable and less prone to this type of testing failure.. artificial
throttling of throughput.

That said, JMeter is still the most useful OSS test harness out there.This is just a question
of knowing the tools strengths and weaknesses.

Regards,
Kirk

On Jun 23, 2011, at 9:17 AM, Felix Frank wrote:

> On 06/22/2011 06:13 PM, jsheth wrote:
>> Also, if I run jmeter with 200 users, do I have to tweak anything in
>> apache/tomcat on webserver so that it can handle 200 users? What is the
>> default # of users the apache/tomcat can handle at once?
> 
> Usually you test the other way around: You raise the number of requests
> until you hit a performance plateau or things go bad. You do this after
> tuning your servers. It will give you an idea of how much load the
> server can sustain.
> 
> There is no usual "number of users". It all depends on the application,
> the hardware, user behaviour...
> 
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