Re: Tomcat (and JAR) running a bit slow on what ought to be a fast box

[Jim Oberholtzer <midrangel@xxxxxxxxxx>]

That could be quite a laundry list of them.

V5R4/V6/V7 ?

First I would start with where are the JVMs running?  *BASE (which is 
the default) is usually bad since it then competes with everything 
else.  Which Java?  64bit/32Bit?  Two things affect Java performance 
more than anything else, first Memory/Activity Levels.  If there is not 
enough memory and then activity levels in the pool where the java runs, 
bad things happen.  I have clients running almost all the levels of Java 
at some point and all of them will work much better with a dedicated 
memory pool with a high enough activity level.  Remember also the 
garbage collection and those processes need activity level just as the 
application does.  There are tools to find out how often garbage 
collection runs and how big the heap size is and how full the heap is.  
You might get some of those tools working to help you out.

Second is IFS performance.  Sadly the IFS just does not perform as well 
as the Unix/Window file system cousins do.  If there is quite a bit of 
IFS (as opposed to DB/2 which can be very fast) there's not much you can 
do but tune the servers to have sufficient I/O.

It sounds like this system should have sufficient Disk arms but if each 
partition has been skinnyed down to far disk arms might be an issue.

All guesses, but those are the first couple of things I look at.

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


On 3/5/2012 5:09 PM, James Lampert wrote:
> A customer has a 36-CPU MMB, with 10 LPARs on it, running V7. It seems
> peppy enough running our CRM product in QINTER, but when running
> anything in Java, it's slower than our own V6 box (a 1-CPU E4A with only
> one LPAR).
>
> Any suggestions?
>
> --
> JHHL
> --