On Tue, Feb 25, 2014 at 1:59 PM, Ben <Benjamin.M.Auer@xxxxxxxx> wrote:
> This is long shot but here it goes.
> We recently tried updating netcdf to version 4.3.1.1 from version 4.2.1 in
> the base libraries in the GEOS model. We found that when trying to create a
> diagnostic output file we were getting a crash in line 288 of nc4var.c
> which looks like it has something to do with choosing a chunk size. When
> it crashed we were in the call to create the time variable in the file with
> an nf_def_var call. Version 4.2.1 and earlier were running fine. The
> interesting thing is that the time is an unlimited dimension. When we
> changed the time variable to a fixed length dimension 4.3.1.1 ran fine.
> Unfortunately we have not been able to reproduce this in a small example
> program but has there been some change underneath the hood that that might
> have occurred that we should be taking a look at?
>
There was a discussion on this list a little while back (november?) about
the default chunking for unlimited variables. The default was 1, which is
OK for, say, a 3-d variable with one unlimited dimension but horrible for a
1-d unlimited variable.
I _think_ there was mention of patching that code, so it may have
broken something. though I can't find that reference anywhere.
Have you tried explicitly setting the chunking on time with it set to
unlimited? You probably want to do that anyway, at least the old default
was really bad for 1-d unlimited variables.
-Chris
--
Christopher Barker, Ph.D.
Oceanographer
Emergency Response Division
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