I guess it could depend on the MPI library, but most likely not. What parallel file system is used on the customer's machine? Mark
On Tue, Oct 26, 2010 at 7:25 PM, Dave Wade-Stein <[email protected]> wrote: > Mark, > > The same code hangs on the customer machine, but works fine on our clusters. > Would that be possible if some subset aren't participating in the I/O? > > Thanks, > Dave > > On Oct 26, 2010, at 5:14 PM, Mark Howison wrote: > >> Hi Dave, >> >> One common hang with collective-mode parallel I/O in HDF5 is when only >> a subset of processes are participating in the I/O, but the other >> processes haven't made an empty selection (to say that they are not >> participating) using H5Sselect_none(). Also, have you tried >> experimenting with collective vs. independent mode? >> >> Mark >> >> On Tue, Oct 26, 2010 at 6:52 PM, Dave Wade-Stein <[email protected]> wrote: >>> We use hdf5 for parallel I/O in VORPAL, our laser plasma simulation code. >>> For the most part, it works fine, but on certain machines (e.g., early Cray >>> and BG/P) and certain types of filesystems, we've noticed that parallel I/O >>> hangs, so we instituted a -id (individual dump) option which causes each >>> MPI rank to dump its own hdf5 file, and once the simulation is complete, we >>> merge the individual dump files. >>> >>> We have a customer for whom parallel I/O is hanging, and they are using -id >>> as described above. We're trying to pinpoint why parallel I/O is not >>> working on their system, which is CentOS 5.5 cluster. >>> >>> In the past we ourselves have had problems with parallel I/O failing on >>> ext3 filesystems, so we reformatted as XFS and the problem went away. Our >>> customer did this, but the problem still persists. >>> >>> Anyone have any words of wisdom as to what other things could cause >>> parallel I/O to hang? >>> >>> Thanks for any help! >>> Dave > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org > _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
