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

> Unidata netCDF Support wrote:
> > 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
> >
> 
> Hi Russ
> 
> Thanks for the response. I did the test and the system is able to write
> large files. Unfortunately, I can't provide a test code which reproduces
> the problem reliably, because it does not occur every time in my
> production code. What I will do as a temporary workaround is to split
> the output into files < 2 GB, which fortunately is easy to do, and see
> if the problem still occurs. If that is the case I would compile a more
> recent version of the netCDF library as you suggest on the production
> machine. The problem does not occur on my workstation, where I am using
> netCDF 4.0, but which is also a different architecture.
> 
> Jan

Howdy Jan,

I strongly suggest that you upgrade to the latest version of netCDF and see if 
this problem goes away.

Thanks,

Ed

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