We had a similar issue with an application running on a linux server making an ODBC connection to DB2 taking a lot of CPU. We could not find a way to limit CPU so we did what you are considering and created a subsystem for just these jobs and setup a class that ran them at a priority lower than any other job on the system and with a low timeslice. I didn't stop the high CPU use but did stop the impact the job had on other activity on the system
________________________________________
From: MIDRANGE-L [midrange-l-bounces@xxxxxxxxxxxx] on behalf of Lance Gillespie [LGillespie@xxxxxxxx]
Sent: Wednesday, April 06, 2016 5:17 PM
To: 'midrange-l@xxxxxxxxxxxx'
Subject: IBM i work management
We are using a third-party tool (Cognos BI) to
allow end-users to develop custom reports.
As users will, they sometimes make an ill-formed
query that consumes excessive resources on our
IBM i (V7R1 going to 2 when the ERP vendor is ready).
By excessive I mean 98% cpu consumed by two or
three jobs.
We would like to isolate this task to a subsystem that
has limited CPU and/or IO max so other users are not
bothered.
The job is a QZDASOINIT prestart job and the user ID is
known. We don't have any experience working with
IBM i work management tools.
Where would I look and what would I have to do to
limit the impact of these jobs? It seems like maybe
create a subsystem (but CRTSBSD does not seem to
have a CPU MAX parameter) and direct the jobs to
it somehow?
They use the QDFTSVR job description, but CHGJOBD
does not seem to have a CPU MAX parameter either.
I see CPU mention in the class description, but it is
for CPU used. We don't care how long the jobs
take or how much CPU they eventually consume
doing it, just that at no time are they ever responsible
for more than say 25% of the CPU. All of these jobs
in aggregate. One by itself could consume 25%, but
if another one started up they would have to share
the 25%.
We don't have multiple cores so it does not seem that
we can use Workload Capping Groups.
Any ideas?
Thanks,
lance
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