I should mention that in my case, I am brutal. I use ramp up, but I
don't use timers. I tend to shoot for worse case scenario to expose
flaws, weaknesses and memory leaks in the dev and staging environment.

I usually try to shoot for better performance than the requirements.
If my stress tests handle the worse case test, I usually feel
confortable standing by the performance of the application. If it just
barely meets the requirements, I usually state a lower number for
sanity sake.

I might be paranoid.

peter


On Thu, 15 Jul 2004 13:51:57 -0400, Michael Stover <[EMAIL PROTECTED]> wrote:
> If you are on 3Ghz p4 with 1G, I would expect you can run more than 100
> users.  I've run up to 500 with reasonable success (you can't trust the
> absolute timings on it, but it doesn't chug badly or crash).
> 
> However, it's all highly dependent on the test details.  A test that
> parses responses for embedded resources is going to kill JMeter's
> performance a lot faster than one that doesn't.  Regular expression
> parsers, assertions also add significant processing time for JMeter.  A
> complex test might have 100 users as a max on that machine.  A simple
> test might allow up to 500 users.
> 
> It also depends on how fast the server is - a faster server puts more
> stress on JMeter because each thread spends less time blocked on IO and
> more time preparing the next request.
> 
> And, of course, timers.  A test without timers is brutal for both
> sides.  A few timers increases dramatically the number of users that can
> effectively be simulated.
> 
> I think the biggest lingering limitation of JMeter is that the remote
> testing feature was not adequately made, and does not in fact get you
> anything in terms of scaling tests up.
> 
> -Mike
> 
> 
> 
> On Thu, 2004-07-15 at 13:05, joelsherriff wrote:
> > Agree - my background is in writing commercial test tools - was team lead
> > for Compuware on the web team for QALoad, before that with
> > Rational/Pure/Performix (way way back when).  So the big tests 1000+ users
> > are what I'm used to dealing with.  Right now I've been asked to evaluate
> > jmeter against the commercial tools and scalability is always the killer -
> > esp when you look at the tools that drive the server by driving instances of
> > a browser (yuck!).  I'm really liking jmeter - much better than I expected
> > it to be.  I expected to find lot's of holes and limitations (the arrogance
> > of the old-timer) but really haven't seen any that aren't there for pretty
> > good reason - like the proxy/ssl issue.
> >
> > To distill down something you said, and ignoring the network limitations
> > (since that's such a variable):  so in your experience you get about 100
> > threads per machine before it saturates it?  Is it typically CPU bound or
> > memory or...?
> >
> > J
> >
> > ----- Original Message -----
> > From: "Peter Lin" <[EMAIL PROTECTED]>
> > To: "JMeter Users List" <[EMAIL PROTECTED]>
> > Sent: Thursday, July 15, 2004 11:43 AM
> > Subject: Re: Any other limitations of jmeter? How about scalability?
> >
> >
> > > for general performance testing stuff, I have several performance
> > > articles listed on the links page
> > > http://wiki.apache.org/jakarta-jmeter/JMeterLinks.
> > >
> > > If I compare JMeter to other tools I've used, I would say it is
> > > comparable. The tools I've used:
> > >
> > > 1. apache ab
> > > 2. zdnet Webbench
> > > 3. custom script perl
> > >
> > > The biggest challenge of stress testing is this, "what are you
> > > testing?"  Most of the time, the bottleneck for a website is the
> > > connection to the internet. I have a explanation of it in the
> > > articles. It doesn't really matter if your website can handle 80
> > > concurrent requests reliably, if you're server is on a T1. I would say
> > > JMeter can easily produce enough stress to figure out what the upper
> > > limit is for your web application. The situations where it won't be
> > > suitable is if you're testing a system that has to support 5,000
> > > concurrent users. You still could use JMeter if you setup each
> > > instance with 100 threads and use 50 machines.
> > >
> > > realistically, to do that kind of test, the server would have to be a
> > > big Unix box or mainframe hooked up to several gigabit routers. Using
> > > 100mbit ethernet, you wouldn't be able to test 5K concurrent requests
> > > for a sustained period of time effectively. Sustained transfer rate
> > > plays a huge role in how many concurrent requests a system can handle
> > > reliably for a long time.
> > >
> > > peter
> > >
> > >
> > >
> > > On Thu, 15 Jul 2004 11:25:50 -0400, joelsherriff
> > > <[EMAIL PROTECTED]> wrote:
> > > > After Peter pointed out that the jmeter proxy doesn't do ssl, I thought
> > I'd
> > > > ask everyone if they know of other limitations they've run into and
> > about
> > > > what seems to be the cronic limitation of these tools - scalability.
> > Not
> > > > talking about bugs per se, just things you might have been able to do
> > with
> > > > other tools you can't do with jmeter.  Like, does jmeter support NTLM
> > > > authentication?  (I realize that's a question, not a statement, but some
> > > > other tools have problems with NTLM so I thought I'd throw it out
> > there.)
> > > >
> > > > As to scalability...How many users can you emulate before saturating
> > your
> > > > driver machine given an "average" script (mix of text and graphics,
> > etc)?
> > > > Given something like a 3Ghz P4 with 1M of memory.
> > > >
> > > > I originally did intend to play with jmeter more and lurk on this list
> > much
> > > > longer before asking these types of questions, but, as always, it's
> > faster
> > > > to ask...
> > > >
> > > > J
> > > >
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> > > >
> > >
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> > >
> > >
> >
> >
> >
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> --
> Michael Stover <[EMAIL PROTECTED]>
> Apache Software Foundation
> 
> 
> 
> 
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