Depends, we are currently in the progress of migrating away from COBOL to
EJB servers. However, rather than the all-or-nothing approach we are
conducting a phased approach whereby we slowly remover functionality away
from COBOL and implement in Java.
One of the difficulties we faced was that our particular COBOL environment
was ill-suited to "wrapping" java objects around. We spent a year looking at
this and finally came to the conclusion that replacing the COBOL servers one
at a time was the best approach. Admitedly, we could not take advantage of
CORBA or JNI as this was not supported at the time for our COBOL
environment.
If however CORBA, JNI or other technologies such as Tuxedo gateways to Java
or CICs gateways to Java exist it would be prudent to follow Ian's advice.
Alas, we did not have this luxery.
Probably the single BIGGEST worry is resourcing. If your current staff are
COBOL people with little or no Java/OO experience then some
training/mentoring is vital. I have found that given a reasonable EJB/OO
model/framework and some mentoring most of the COBOL people will try to make
the effort to come up to speed, plus you can also grab some Java architect
contractors etc.
I also looked at transactional throughput and we are using Weblogic which I
think, with careful design, will handle the load you are talking about.
Remember that these servers are multi-threaded and will take advantage of
(well at least in the case of Solaris) native threads extensions, which
allows the scalability you desire. There is also clustering...
Just my $0.02 worth :)
Regards
Rob Masters
Sun Certified Java Programmer
Comcare Australia
(w) 02 6275 0632
(f) 02 657 4045
[EMAIL PROTECTED]
http://www.comcare.gov.au
> -----Original Message-----
> From: Ian McCallion [SMTP:[EMAIL PROTECTED]]
> Sent: Monday, 24 May 1999 19:59
> To: [EMAIL PROTECTED]
> Subject: Re: ADVICE
>
> John Geurink wrote:
>
> > I'm new to your group and this technology and find it very interesting.
> > We are undertaking a development effort to move from our traditional
> two-tier
> > procedural based architecture to a three tier object based. We will be
> > kicking off a pilot project that will try and develop EJB's that will
> replace
> > pieces of our COBOL system. Our concern deals with transactional
> capacity.
> > We are unsure of Java's ability to handle large amounts of data and
> > transactions. The system that we build, has to be scaleable. We have
> clients
> > that produce 1,000 to 250,000 transactions a day. How much of the
> > scalability falls on the Web Application Server's ability to scale/load
> > balance? When it gets right down to it, you can't just "throw more
> hardware"
> > at it. We have talked to several industry leading vendors and
> practitioners
> > but have yet to get a resounding YES. We do have a better feeling about
> this
> > after our meeting with WebLogic last week. Can anyone give me a feel
> for
> > EJB's ability to handle this type of application?
>
> John,
>
> I have little doubt that EJBs could handle 250K transactions/day, provided
> you follow good design principles for scaleable transactional design
> (which
> will not be the design that emerges naturally from OO modelling, by the
> way).
>
> But I doubt the wisdom of throwing away your COBOL at this time. Of course
> I don't know the full situation, but most
> "throw-it-all-away-and-start-again" projects fail to meet objectives or
> fail completely because of the phenomenal challenges of achieving, in one
> go, equivalence or better to something honed over many years.
>
> So my advice would be to start using EJB, but to "wrapper" the existing
> application in order to add new capabilities.
>
>
> Ian McCallion
> CICS Business Unit
> IBM Hursley
> [EMAIL PROTECTED]
> Tel: ++44-1962-818065
> Fax: ++44-1962-818069
>
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