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Re: troubles stopping ldm with ldmadmin on linux (fwd)

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  • Subject: Re: troubles stopping ldm with ldmadmin on linux (fwd)
  • Date: Thu, 18 May 2000 10:08:59 -0600 (MDT)

===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================

---------- Forwarded message ----------
Date: Wed, 17 May 2000 17:53:25 -0500 (CDT)
From: David Wojtowicz <address@hidden>
To: address@hidden
Subject: Re: troubles stopping ldm with ldmadmin on linux

On Wed, 17 May 2000, D. J. Raymond wrote:

> I also see this on my Debian Linux box.  I suspect that the processes
>  won't die until some crucial I/O is done -- probably a good thing!
>  Why it takes longer on Linux than on Solaris, I do not know.  Maybe
>  it is a matter of writing stuff from virtual memory to disk, which
>  could take a long time if, say, 50 MB or so of the product queue were
>  memory mapped.  The time to die is quite variable -- if the ldm has
>  just been started, the processes die quickly, but if it has been
>  running for a while, they take longer.
> 

It used to do this under Redhat Linux.  If a large product queue was
being used on a large memory machine and the processes had touched a 
significant portion of it, you'd have to wait while all those MB where
flushed back to disk whenever you killed off LDM before the processes
would actually go away.   In this case you should observe constant
disk activity until the processes finally exit.  We found a relatively
simple fix for this under Redhat.  (It selects a different product
queue flag when configuring for compilation)  Perhaps when compiled
under other versions of Linux this flag is not set?

--------------------------------------------------------
 David Wojtowicz, Research Programmer/Systems Manager
 Department of Atmospheric Sciences Computer Services
 University of Illinois at Urbana-Champaign
 email: address@hidden  phone: (217)333-8390
--------------------------------------------------------