[Pvfs2-users] The unexpected results of running MPI-IO on PVFS2

[Robert Latham]

Hi xuechen.  You asked good questions so I'm bringing this back to the
pvfs2-users list where others can benefit:

On Tue, Nov 20, 2007 at 03:42:44PM -0500, xuechen zhang wrote:
> Right now, I am doing experiment on PVFS2 using 'mpi-io-test' which
> is provided by PVFS2 itself. While I just 'pvfs2-cp' a large file to
> '/mnt/pvfs2/'by default, how can I find out the striping parameters
> by using the command of pvfs2 or something other ways? I have tried
> to use 'pvfs2-stat' which shows information below, however that is
> not what I want, such as strip size.

There is a utility called 'pvfs2-viewdist' which should tell you want
you want.

> And also, is there only PVFS2 API that can set the configuration of file
> on PVFS2? 

You can use extended attributes on a directory.  This entry has more
information:

http://pvfs.org/doc/pvfs2-faq/index.php#sec:dir_tuning

> And I also cannot find the detail description of PVFS2 API.
> Could you please show me where it is?

We call the PVFS API the "system interface".  It's pretty low level
and probably not what you want to use.  MPI-IO is a lot easier, even
for serial programs.

The ROMIO "ad_pvfs2" driver has examples of how to use the system
interface.  The 'pvfs2-sysint.h' header file has all the prototypes.
You can also see what the test and admin programs do.  

If you run into more problems don't hesitate to ask.
==rob

-- 
Rob Latham
Mathematics and Computer Science Division    A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA                 B29D F333 664A 4280 315B