This is true. I think a lot of us just worry about the cost of RMI too much.
Is it noticeable to the user? No, probably not. Right now we sit at about
300 concurrent sessions though and the cost of RMI then becomes pretty high.
(actually I think you can actually go higher than 50 concurrent users. there
will be an initial hit as they access the site, but then there will be some
down time as they view and decide what to do next)
Scalability is good with EJB, and it is HOT technology, one just needs to be
aware of the costs involved in that. On the clustering side that is exactly
why we are using EJB. You start to become overloaded in resources you just
through another server onto the network. So yes, what you say about that is
absolutely true.
Actually a lot of my concerns about RMI costs and such are coming from a
recent interview I had which made me think of some things. Some I have
rethought and have come to the conclusion they were not exactly correct. But
then EJB is so new to both me (I've only been using the technology a few
months and just moved to the 1.1 spec) and the place I interviewed at that I
had to do some tests to see if the theorys were true or false. :) The cost
in network traffic using RMI is not going to go away, the question becomes
is that cost higher than we can affford or is the scalability important
enough to warrant that higher cost. Personally I don't think that the cost
is any worse than using JSP's or servlets. But I have not actually done any
timing or performance tests. The advantage in my mind at least is the
database pooling Which is also why I am such a fan of Stateless session
beans. Pooling is much easier and less costly with them than with stateful.
Anyway I babble. Yes, everything you say is correct. Some of us just try to
get every ounce of power possible from what we have. :) Sometimes that tends
to make us worry worts. Jens probably has some figures on the costs and
such, he has done much testing lately with these things.
Al
----- Original Message -----
From: Kevin Duffey <[EMAIL PROTECTED]>
To: Orion-Interest <[EMAIL PROTECTED]>
Sent: Sunday, April 02, 2000 6:43 PM
Subject: RE: EJB Question(s)
> Ok..you've got me concerned here. I thought EJB was all the rage right
now,
> which is the big reason everyone is going to it. But, you and some others
> have been saying lately that its slow compared to other solutions.
>
> The question is, is it slow only because of network traffic? I mean, we
have
> a T1 line, which is 1.5Mbps, but our network is 100Mbps, so if everyone is
> using 56K modems hitting our site, thus, about 50 people can use our site
> via T1 at the exact same moment, how is it being such a bottleneck to the
> 100Mbps network behind the scenes?
>
> Plus, from what I read, the reason to go to EJB is so you can scale the
> hardware and the app server on each machine works together to keep the
same
> session from the client-side going to the right machine on the EJB tier,
and
> thus as you scale and add more machines, you can handle more. Is this not
> the case now?
>
> Another question arises here. Doesn't the EJB server handle scalability
> automatically? Meaning, if I add another machine, is it alot of work to
get
> a new app server installed and working with an existing one, so that the
> requests are divided between the two app servers now?
>
> Thanks.
>
>
