Re: One Extremely Busy Disk -- MIDRANGE-L

Of course, when you said shift change, the first thing that comes to mind is
the signoff operations. These would cause forced writes to the files.

I assume you have the performance tools on your system. You can use them to
locate the file(s) that is(are) being hit on that drive, but first, ask
yourself, what JDE file keeps track of signed on users....



===========================================================
R. Bruce Hoffman, Jr.
 -- IBM Certified Specialist - AS/400 Administrator
 -- IBM Certified Specialist - RPG IV Developer

"America is the land that fought for freedom and then
  began passing laws to get rid of it."

     - Alfred E. Neuman

-----Original Message-----
From: prumschlag@phdinc.com <prumschlag@phdinc.com>
To: MIDRANGE-L@midrange.com <MIDRANGE-L@midrange.com>
Date: Friday, March 23, 2001 9:25 AM
Subject: One Extremely Busy Disk


>
>
>We have been having an intermittent response time problem lately that
always
>seems to happen around 7:00 AM.  This is shift change time in the factory,
so
>there is plenty of activity on the system (in other words, tough to tie the
>problem to one user or job).  I have looked at the Ops Nav monitors and one
>thing looks out of kilter.  At about this time, one of the disk drives gets
very
>busy for a short period of time, usually 30 to 60 seconds.  This morning
was the
>worst I have seen: a full three minutes at 90% busy.  In the four days that
I
>have watched it, it has always been disk # 21 or 37.  Our journals are in a
>separate ASP, not one of these drives.  I know of no jobs that we have
setup
>that would force a write to the disk for every record update.  That does
not
>mean we don't have any, it just means I may not know about it.  CPU
activity
>looks normal during this time frame.  Disk Utilization is around 80% .
>
>Now that I have rambled on, three more specific questions:
>
>   1.  We don't normally watch disk drive activity, because it just usually
is
>   not a problem so I don't know if this is a normal occurrence or not.  Is
this
>   a red flag?
>
>   2.  How can I tie the activity on the disk back to a specific job
causing the
>   activity?
>
>   3.  Could there be some kind of system activity that is forcing a disk
>   read/update to the same record?  Is it time to get IBM involved?
>
>We are running J D Edwards World on  a V4R3 model 730, with 48 disk drives
(
>6607-070's, 072's, and 074's) with RAID active.
>
>Phil Rumschlag
>
>
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