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[LDM #RZU-177693]: LDM 6.9.7 bug: file writing problem

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  • Subject: [LDM #RZU-177693]: LDM 6.9.7 bug: file writing problem
  • Date: Wed, 23 Mar 2011 10:55:11 -0600
Gilbert,

> We have an issue here at AllisonHouse whereby we write a 5 minute-updating
> Iowa mesonet file to /home/ldm/data/gempak/surface/iowa.txt.  It never
> gets rotated out, so of course, it can get very large. We have a
> crontab entry that faithfully scours it daily, and retouches it with a
> zero-length file:
> 
> 49 6 * * * rm -f /home/ldm/data/gempak/surface/iowa.txt;touch
> /home/ldm/data/gempak/surface/iowa.txt
> 
> But after we do this, it will *not* repopulate with data! It stays a zero
> length file, and there
> are no errors in ldmd.log. However...
> 
> When we do an ldmadmin stop, clean, and start...then it populates/writes to
> the file again.
> 
> Again, I fully realize we are a .com and expect no support from this, but I
> figured you'd want to know.
> We are running RHEL 5.6.

On UNIX systems, a file that a process has open for writing can be removed and 
recreated without affecting the process: it will continue to write to the (now 
invisible) file. Only when the process closes the file will it be actually 
deleted from the file system. Consequently, if you're writing to the file via a 
pqact(1) FILE action, then you should ensure that the action has the "-close" 
option.

> Gilbert Sebenste
> Chief Meteorologist
> AllisonHouse, LLC

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: RZU-177693
Department: Support LDM
Priority: Normal
Status: Closed