Re: JVM on i-Series

Collin, Pat

thanks a bundle for your comments. At least it confirms I'm looking in
the right direction. Today I'll dig in to the "how".

Sacha

2006/3/18, PatM <pat@xxxxxxxxxxxxxxx>:
> 400-600 jvms?  That's an incredible load!
>
> We have had 2000 or so interactive jobs feeding requests into a data queue
> with a couple of jvms running multithreaded apps (about 50 threads per jvm)
> that make requests out to a webservice on another platform.  Replies have
> been put onto a keyed data queue so that each interactive job can retrieve
> their own response.
>
> This has been very successful and does not tax the iSeries.  Another method
> of RPG to java communication is sockets.
>
> We isolated our jvms (we have several more running) into their own memory
> pool.  With tuning on this you want to be sure to have enough memory
> allocated to the pool.  You can check this through the STRSST.  There is an
> option that allows one to see the last several garbage collections, GCCycles
> (I can't remember the menu options - reply back if you need it).  This will
> provide the size of the jvm.  As far as processes, you need to count each
> thread and add some for the jvm for the number of concurrent processes.
> This is usually more than enough since all the threads will probably not be
> active all at once.  I will back this down a bit.
>
> When setting up your java app, you need to watch the SQL performance (DBMon
> in Ops Navigator) and also your jvm heap size.  On the heap size, you should
> see a normal saw tooth pattern vs. a heap size that continually grows.  If
> the latter happens, there is something in the app that is not releasing
> memory and some further investigation is necessary with the dump jvm command
> or the analyze jvm command.  If you are unable to determine the cause of the
> growth you can use heap analyzer that is the free part of iDoctor.
> Rochester support is very good and helping with these kinds of problems
> also.
>
> PatM
> -----Original Message-----
> From: wdsci-l-bounces@xxxxxxxxxxxx [mailto:wdsci-l-bounces@xxxxxxxxxxxx] On
> Behalf Of Colin Williams
> Sent: Wednesday, March 15, 2006 6:12 PM
> To: Websphere Development Studio Client for iSeries
> Subject: Re: [WDSCI-L] JVM on i-Series
>
> 400 to 600 JVMs!
>
> Sacha, the background process attached to a dataqueue id definitely the way
> to go, and that gives you the flexibility to add more JVMs listening to the
> dataqueue as and when you need them to meet demand. Its very efficient this
> way and does not overload the system
>
>
> On 14/03/06, Sacha Boer <sachaboer@xxxxxxxxx> wrote:
> >
> > Thanks David,
> >
> > just subscribed.
> >
> > Sacha
> >
> > 2006/3/14, David Gibbs <david@xxxxxxxxxxxx>:
> > > Sacha Boer wrote:
> > > > do any of you have experience with java on the iSeries?
> > >
> > > This question would be better suited to the JAVA400-L list
> > > (http://lists.midrange.com/listinfo/java400-l).
> > >
> > > david
> > > --
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