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[LDM #NNE-789939]: Quick question: what is ipcs trying to tell me here?

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  • Subject: [LDM #NNE-789939]: Quick question: what is ipcs trying to tell me here?
  • Date: Wed, 18 Jul 2007 13:09:57 -0600
Hi Gilbert,

re: unused shared memory segments left over by McIDAS-XCD decoders

> OK, but how does this happen, especially to a guy who writes perfect
> software? ;-D 

The typical way that this can happen is by the processes being terminated
before they cleanup after themselves.  I believe that this has happened
a number of times on weather.admin.niu.edu.  I say this because the listing:

<as 'ldm'>
ls -alt ~ldm/.mctmp

shows more directories than shared memory segments than are currently in
use (the names of the directories match the shared memory segment ID; there
should be a one-to-one correspondence between active shared memory segment
IDs and subdirectories of ~ldm/.mctmp).  Given this mismatch, I would
suggest that you follow the cleanup procedure I sent in my previous email
just to tidy up :-)

> Seriously, though, I don't think I've ever seen this on
> my machines except a few times when I had some nasty memory leaks on
> a kernel (since patched).

If every thing is working correctly, you should never see orphaned shared
memory segments and left over subdirectories of ~ldm/.mctmp.  The fact
that you do have left over subdirectories whose ages span several months
tells me that everything has not worked flawlessly over those same several
months.  But DONT PANIC... the clean up is simple and quick.


Cheers,

Tom
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Ticket Details
===================
Ticket ID: NNE-789939
Department: Support LDM
Priority: Normal
Status: Closed