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20041209: ERC / ERAU NEXRAD2 Feed (fwd)

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  • Subject: 20041209: ERC / ERAU NEXRAD2 Feed (fwd)
  • Date: Thu, 09 Dec 2004 14:34:49 -0700
>From:  Jeff Weber <address@hidden>
>Organization:  UCAR/Unidata
>Keywords:  200412091955.iB9JtfBC001444 LDM NFS mount unmount

Jeff,

>I would not consider NFS mounts for distributed LDM's to be a good
>practice...
>
>Thoughts?

Having the HOME directory of the LDM on an NFS mounted file system can
-- and does -- lead to problems that are difficult to explain to the
non-technical contacts at the site.

What I am thinking of is a situation where the LDM home directory is on
an NFS file system that is automounted AND autounmounted.  Case in
point: Western Michigan University.  What happens is the filesystem
gets unmounted after a certain amount of inactivity.  Why is this bad?
Cron jobs stop working even though the LDM ingest and decoding process
do not (the logs and data directories are on different file systems).
The result:  the file systems where data/decoded data is written fill,
and the system fails.  Again, this is a real world situation that was
happening at W. Michigan.

The solution that Mike S. and I implemented was to run a cron job that
'touch'es a file in the ~ldm directory once-per-minute.  This should
keep the file system active enough that it never gets unmounted.  I
_think_ that this is working at WMU, but I am not 100% sure.

NB: attached references removed to protect the innocent ;-)

Cheers,

Tom.
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