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[netCDF #GCB-165173]: Ticket ID: VIX-344006

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  • Subject: [netCDF #GCB-165173]: Ticket ID: VIX-344006
  • Date: Wed, 30 Sep 2009 10:36:18 -0600
Hi Jan,

> I would like to inquire on the status of my support request regarding a
> failure of the netCDF library that produces the error message
> 
> wrf.exe: posixio.c:232: px_pgin: Assertion `*posp == ((off_t)(-1)) ||
> *posp == lseek(nciop->fd, 0, 1)' failed.
> 
> What is the cause of this failure?

I'm sorry it's taken us so long to respond to your support request from 26 days
ago, it seems to have slipped through the cracks in our support system.

A previous time we saw this assertion violation, it was diagnosed as a problem
with AIX returning an erroneous value from an lseek() call when it was unable 
to write a large file, due to file system misconfiguration:

  http://www.unidata.ucar.edu/support/help/MailArchives/netcdf/msg02656.html

We saw this assertion violation in another case on an HP-UX platform when it
was trying to write a file larger than the 2 GiB limit an older version
of the netCDF library.

From that analysis, I would suspect the file system on which you're trying to
write this file on your Linux 2.6.18-92.1.13.el5 SMP x86_64 platform might
not be properly configured for writing files larger than 2 GiB.

Can you try running the following commands writing a large file on the same
file system you were using when you got the error?  If it was remotely
mounted from a server rather than a local file system, please try to use 
it in the same way when running this command, just to verify whether you can
write large files:

  dd if=/dev/zero bs=1000000 count=3000 of=./largefile
  ls -l largefile
  rm largefile

That should write a 3 GByte file named "largefile" in the current directory, 
verify its size, and remove it.

If that works, then I would suggest upgrading to netCDF 3.6.3 or 4.0.1 and
seeing if the problem still exists.  (4.0.1 built without --enable-netcdf4
will still support your netCDF-3 programs and files by default).

Otherwise, if you could provide us with a small program that demonstrates
the assertion violation, we could try to reproduce it here to diagnose the
problem more completely, although we don't have access to the exact
platform on which you are encountering the problem.

--Russ


Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: GCB-165173
Department: Support netCDF
Priority: Normal
Status: Closed