System hangs and then console too does not respond

Problem Statement::

Sometimes Our  i-series model 820 is not able to properly
allocate/adjust  the
CPU utilization for the jobs running in the system.Because of this system
hangs as a result we have to bring down the system and restart it (IPL).
While teh system hangs even a ping from teh network yields "request Timed
out" and console does not conenct.
This is just our analysis/understanding of the problem.The actual problem
can be something else.

Please find other details that will be helpful for you to understand the
problem in Detail


All of our development projects are running on the secondary partition. (In
this
scenario  AS/400 system operator  looses the control of main console
of secondary partition as the main console of the secondary partition is
attached to a PC so it gets disconnected at this stage when the AS400
cannot allocate adequate CPU to the modem/communication card handling the
Console)
Thus the only option is to abnormally stop the secondary partition using
Primary control panel and again start it.

We have found following instances when this situation happens:

1.While running/compiling some  programs interactively they
start  taking  lot of CPU.When we try to kill that interactive job the CPU
utilization increase and causes the system Halt .We have tried all possible
the ways of Ending the job.

2.Along with some resource hungry Batch jobs(submitted by us)  running in
system , we try to run some more jobs mainly interactive(can be batch
job).In this situations those Batch jobs doesn't automatically adjust the
CPU utilization.

In these situation the Response time of system goes very slow  and
eventually we lose the control of main console of secondary partition.We
have to end and restart the Secondary partition.


We have tried following ways so that system doesn't hang up
1.We consistently monitor the jobs  running on system and used to hold any
job(mainly interactive) which starts taking Lot of CPU.(But this may not be
right approach).Sometime even that is not possible.


The configuration of the i-series we are using is as:

Partitions =2
Model No. - 820
Processors - 2-way, 600 MHz (2437)
Interactive CPW - 240
Interactive Feature - 1524
Processor CPW - 2350
Main Memory - 4GB
Hard Disk - 633 GB
OS/400-V5R2

Please let us know if you need any information that can be helpful for
you.I will be glad to share the same.
request some help please as i believe 400's are too sturdy to behave in
such a way .
I assume something wrong with teh way we are treating it.


Thanks

Ashish  Uchil

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