I'm trying to simulate a cluster setup where only the I/O aggregators have access to the working directory. Is this feasible to do with romio hints? Setup: A) Work dir is on Node0's local hard drive. B) Remote Node1 has no access to Node0's hard drive C) Run a case where only rank 0 on Node0 serves as the I/O aggregator Simple MPI I/O Code: #include "mpi.h" #include <string.h> #include <stdio.h> #include <unistd.h> int main(int argc, char *argv[]) { MPI_File fh; MPI_Info info; int amode, mpi_ret; char filename[64]; MPI_Init(&argc, &argv); MPI_Info_create(&info); MPI_Info_set(info, "cb_nodes", "1"); MPI_Info_set(info, "no_indep_rw", "true"); strcpy(filename, "mpio_test.out"); amode = MPI_MODE_CREATE | MPI_MODE_WRONLY; mpi_ret = MPI_File_open(MPI_COMM_WORLD, filename, amode, info, &fh); if(mpi_ret != MPI_SUCCESS) { char mpi_err_buf[MPI_MAX_ERROR_STRING]; int mpi_err_len; MPI_Error_string(mpi_ret, mpi_err_buf, &mpi_err_len); fprintf(stderr, "Failed MPI_File_open. Filename = %s, error = %s", filename, mpi_err_buf); return -1; } // Force I/O errors associated with this file to abort MPI_File_set_errhandler(fh, MPI_ERRORS_ARE_FATAL); MPI_File_close(&fh); printf("SUCCESS\n"); MPI_Finalize(); return 0; } Note the hardcoded "MPI_Info_set(info, "cb_nodes", "1");" and "MPI_Info_set(info, "no_indep_rw", "true");". The above code runs fine when run from multiple cores on Node0. As soon as I add a Node1 to the mix, I get the following error: jpovich@crane mini_test> mpirun -np 2 -hosts crane,node1 /work/jpovich/box_testing/1970/1970_test [[email protected]] control_cb (pm/pmiserv/pmiserv_cb.c:200): assert (!closed) failed [[email protected]] HYDT_dmxu_poll_wait_for_event (tools/demux/demux_poll.c:76): callback returned error status [[email protected]] HYD_pmci_wait_for_completion (pm/pmiserv/pmiserv_pmci.c:198): error waiting for event [[email protected]] main (ui/mpich/mpiexec.c:344): process manager error waiting for completion The cb_nodes setting seems to have no impact on behavior. I get the same error if I comment out the cb_nodes and no_indep_rw settings. Any help is greatly appreciated, Jon _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss