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
