Re: AS/400 and Java

Hi,

I don't want to raise a flame about whether or not iSeries is a good server
(in general and for Java in particular), because it is more reliable,
scalable, maintainable, blah blah blah... despite the fact it is slower and
much more expensive. I do know there are good reasons why people do use
AS/400, but this is not the question I want to discuss.

I just have told one true story and I can just tell another one if anyone
want to listen.

There were same two machines involved, one is EUR 35K model 270 and next to
it is EUR 1,4K dual Pentium III 733MHz Dell PC with RAID-5 disks.
I'll leave price math to those who cares. :)

Our system is sort of realtime warehouse execution system, that is - there
are many (hundreds) of users. Thus no one dares to say it's single-user
application. :)
Users are wearing portable terminals which go to our system through TCP/IP
to request or to submit information. Our application is sort of
request-response network server with database backend. For simplicity's
sake, you can think about is as special case of Apache/CGI. The application
itself is rather small; JAR with all the libraries it uses is just 1MB in
size. Note that unlike previous case, it is not J2EE, but just plain Java
application.

The simulation was not just a stupid stress load test but very thorough - it
almost 100% resembles actual user workflow.

In first setup, AS/400 was running both database and Java application (with
level 20 optimization).
It took 15 simulated users to go to 100% processor load at AS/400.

In second setup, AS/400 was holding just a database while Java application
was running at PC.
100 users created 10% processor load on PC and 60% processor load on AS/400
mostly at the expense of database jobs.
No changes were done in code, configuration, database schema, etc. etc.
apart from moving Java application to another machine.

So, basically, it is obvious that not the database what creates 100% load at
AS/400 but Java application.



Regards,
Timur

----- Original Message -----
From: "Joe Pluta" <joepluta@PlutaBrothers.com>
To: <java400-l@midrange.com>
Sent: Monday, November 04, 2002 3:10 AM
Subject: AS/400 and Java


> Timor wrote:
> "The major problem is runtime performance. A modest P-III 733 MHz
> outperforms our model 270 at least 5 times (and up to 20 times) on our
> load stress simulations, which mostly make use of JBoss MQ and data
> queues through JT400."
>
> And Stefan replied:
> "thanks for your hints. I understood the IBM papers that  AS 400 is a
really
> fast  machine for java. But looks like it isn't."
> =========
>
> Hopefully one of the real heavyweights on Java performance will step in
here
> at some point (where are ya when we need ya, Blair???), but let me give
you
> my own less-than expert opinion.  In rality, the iSeries JVM is very
> powerful, very scalable and very fast.  You have to be careful what you're
> measuring when you compare PCs and midranges, though.
>
> Timur is comparing the iSeries model 270, a single processor midrange
> server, with a dedicated PC running a JVM.  That's usually an unfair
> comparison, because the dedicated PC isn't doing any of the things the
> AS/400 is doing in the background, and isn't capable of doing them, which
is
> why it can do one thing very fast.
>
> The tradeoff for a midrange system is the ability to easily scale as
opposed
> to a low price for a small number of users.  With an AS/400, you can add
> literally dozens of processors, to increase your capabilities hundreds or
> even thousands of times.  Try that with your 733MHz PC, or even a PC
> network.
>
> The iSeries is not a single-task dedicated machine.  It is a business
> server, and for that reason, raw single-use performance comparisons are
> meaningless.  For example, does your PC have a built-in database?  No.
You
> have to add that.  And tune it.  With the iSeries, it's all right there.
> Can you run multiple partitions with your PC?  Piece of cake with the
> iSeries.  Do you have object level security?  An RPG compiler?  5250
> interface?  Nope.  Do you have hot-swap RAID drives?  Automatic disk arm
> balancing?  Automatic system tuning?
>
> All of this comes with the iSeries.  Because of that, it really doesn't
show
> its colors until you have a few dozen users.  It's kind of like an old car
I
> had - a 1972 Buick Electra 225 with a Wildcat 445 engine.  From 0-50, it
> wasn't very quick, because it was a big, heavy car.  But from 50-90, there
> wasn't a car on the highway that came close, even the fancy muscle cars.
> See, the 225 was designed to be driven fast for a long time, and that's
sort
> of what the iSeries is built for - lots of user with lots of uptime.
>
> So if you're looking for a server to replace something that's running fine
> on a single-PC J2EE server, then the iSeries is probably the wrong way to
> go.  I'd have to know more of the architecture to be sure, because I'm
> assuming Timur doesn't need the database or security of an iSeries.  That
> being the case, we could have a long discussion on why anyone would write
a
> J2EE application that can run on a single PC, but that's a different story
> for a different day.
>
> Now, if your application makes heavy use of a real enterprise database, or
> you may need to scale up to dozens or hundreds of users, or you need 24/7
> uptime, or you want to use business languages such as RPG or COBOL for
your
> business rules, then you might want to look into the iSeries.  The
iSeries'
> strength is not in the fact that you can throw together a quick, cheap
> solution with little or no programming.  Instead, the iSeries strength
lies
> in its ability to integrate all the latest technologies, from Java to
Linux,
> along with proven legacy techniques such as RPG and COBOL, to allow you to
> create powerful, scalable applications.
>
> Or, you might want to have a server farm running an EJB application on a
> bunch of PCs (thus providing failover), but all communicating with an
> iSeries in the background for pure database and business logic serving.
> That's a possible architecture, but it requires more than a simple stress
> tester to determine whether it's the right architecture for you.
>
> You really have to take the time to determine your business requirements
> before you can even begin to compare servers.  Once you determine your
> actual hardware needs, you may find that you have to compate the total
cost
> of ownership of an iSeries as opposed to a PC server farm with, say, a
dozen
> PCs.
>
> On the other hand, if it turns out your application fits on a single PC,
> then I doubt that you need an iSeries.  Instead, you might want to
consider
> something more appropriate, like Microsoft IIS and Visual Basic.
>
> Joe
>
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