pnetcdf and mvapich2 2.2

[Mark Dixon]

On Fri, 3 Feb 2017, Wei-keng Liao wrote:
...
> The Lustre driver in mvapich2 appears to append O_CREAT to the open 
> mode, (line 50, in file src/mpi/romio/adio/ad_lustre/ad_lustre_open.c), 
> even if the file is open for read-only. This is the root cause of one of 
> the error messages you are seeing:
>   "expect error code NC_ENOENT but got NC_ENOTNC"
>
> Attached is a small MPI program to verify such error. Could you please
> give it a try on your mvapich2 build and Lustre?
> Compile command:
>    mpicc test_open_no_such_file.c -o test_open_no_such_file
> Run command:
>    mpiexec -n 1 ./test_open_no_such_file /lustre/path/non-exist-file

Hi Wei-keng,

When I try it with mvapich2 2.2, I see this (/tmp is ext4, /nobackup is 
Lustre):

$ mpicc test_open_no_such_file.c -o test_open_no_such_file

$ mpiexec -n 1 ./test_open_no_such_file /tmp/non-exist-file-on-ext4
non-exiting file "/tmp/non-exist-file-on-ext4"
MPI error string: File does not exist, error stack:
ADIOI_UFS_OPEN(69): File /tmp/non-exist-file-on-ext4 does not exist
Error class = MPI_ERR_NO_SUCH_FILE

$ mpiexec -n 1 ./test_open_no_such_file /nobackup/non-exist-file-on-lustre
Open non-existing file /nobackup/non-exist-file-on-lustre unexpected succeeded

$ ls -l /tmp/non-exist-file-on-ext4 /nobackup/non-exist-file-on-lustre
ls: cannot access /tmp/non-exist-file-on-ext4: No such file or directory
-rw-r--r-- 1 foobar foo 0 Feb  6 12:53 /nobackup/non-exist-file-on-lustre

Thanks!

Mark