Cannot write more than 512 MB in 1D



we are experiencing problems writing “large” 1D datasets on 64bit Linux systems when local writes exceed 512 MBytes or 134217728 elements for 4-byte int/float (1D dataspace) for local MPI ranks.

To reproduce, please see the following one-MPI-rank example, running with HDF5 1.10.4 and OpenMPI 3.1.3 on a 64bit Debian Linux 9.5 with 16 GByte RAM.

#include <mpi.h>
#include <hdf5.h>

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

int write_HDF5(
    MPI_Comm const comm, MPI_Info const info,
    int* data, size_t len)
    // property list
    hid_t plist_id = H5Pcreate(H5P_FILE_ACCESS);

    // MPI-I/O driver
    H5Pset_fapl_mpio(plist_id, comm, info); 

    // file create
    char file_name[100];
    sprintf(file_name, "%zu", len);
    strcat(file_name, ".h5");
    hid_t file_id = H5Fcreate(file_name, H5F_ACC_TRUNC,  
                              H5P_DEFAULT, plist_id); 

    // dataspace
    hsize_t dims[1] = {len};
    hsize_t max_dims[1] = {len};
    // hsize_t* max_dims = NULL;
    hid_t filespace = H5Screate_simple(1,
    // chunking
    hid_t datasetCreationProperty = H5Pcreate(H5P_DATASET_CREATE);

    // dataset
    hid_t dset_id = H5Dcreate(file_id, "dataset1", H5T_NATIVE_INT,  
                              filespace, H5P_DEFAULT,
                              datasetCreationProperty, H5P_DEFAULT);
    // write
    hid_t dset_plist_id = H5Pcreate(H5P_DATASET_XFER);
    H5Pset_dxpl_mpio(dset_plist_id, H5FD_MPIO_COLLECTIVE); 
    // H5Pset_dxpl_mpio(dset_plist_id, H5FD_MPIO_INDEPENDENT); // default

    herr_t status;
    status = H5Dwrite(dset_id, H5T_NATIVE_INT, 
                      H5S_ALL, filespace, dset_plist_id, data); 

    // close all
    status = H5Pclose(plist_id);
    status = H5Pclose(dset_plist_id);
    status = H5Dclose(dset_id);
    status = H5Fclose(file_id);

    return 0;

int main(int argc, char* argv[])

    MPI_Comm comm = MPI_COMM_WORLD; 
    MPI_Info info = MPI_INFO_NULL;  

    MPI_Init(&argc, &argv);
    size_t lengths[3] = {134217727u, 134217728u, 134217729u};
    for( size_t i = 0; i < 3; ++i )
        size_t len = lengths[i];
        printf("Writing for len=%zu ...\n", len);
        int* data = malloc(len * sizeof(int));
        for( size_t k=0; k<len; ++k)
            data[k] = 420;
        write_HDF5(comm, info, data, len);
        printf("Finished write for len=%zu ...\n", len);

    return 0;
$ h5pcc phdf5.c && ./a.out
Writing for len=134217727 ...
Finished write for len=134217727 ...
Writing for len=134217728 ...
Finished write for len=134217728 ...
Writing for len=134217729 ...
HDF5-DIAG: Error detected in HDF5 (1.10.4) MPI-process 0:
  #000: H5Dio.c line 336 in H5Dwrite(): can't write data
    major: Dataset
    minor: Write failed
  #001: H5Dio.c line 828 in H5D__write(): can't write data
    major: Dataset
    minor: Write failed
  #002: H5Dmpio.c line 671 in H5D__contig_collective_write(): couldn't finish shared collective MPI-IO
    major: Low-level I/O
    minor: Write failed
  #003: H5Dmpio.c line 2013 in H5D__inter_collective_io(): couldn't finish collective MPI-IO
    major: Low-level I/O
    minor: Can't get value
  #004: H5Dmpio.c line 2057 in H5D__final_collective_io(): optimized write failed
    major: Dataset
    minor: Write failed
  #005: H5Dmpio.c line 426 in H5D__mpio_select_write(): can't finish collective parallel write
    major: Low-level I/O
    minor: Write failed
  #006: H5Fio.c line 165 in H5F_block_write(): write through page buffer failed
    major: Low-level I/O
    minor: Write failed
  #007: H5PB.c line 1028 in H5PB_write(): write through metadata accumulator failed
    major: Page Buffering
    minor: Write failed
  #008: H5Faccum.c line 826 in H5F__accum_write(): file write failed
    major: Low-level I/O
    minor: Write failed
  #009: H5FDint.c line 258 in H5FD_write(): driver write request failed
    major: Virtual File Layer
    minor: Write failed
  #010: H5FDmpio.c line 1844 in H5FD_mpio_write(): file write failed
    major: Low-level I/O
    minor: Write failed
Finished write for len=134217729 ...

$ du -hs 13421772*                                              
513M	134217727.h5
513M	134217728.h5
4,0K	134217729.h5

Do we miss anything that needs to be passed to write more than 512 MByte from a rank for a single dataset?


We just found it’s even more confusing since in the lengths:

size_t lengths[5] = {134217727u, 134217728u, 134217729u, 134217736u, 134217737u};

the sizes 134217729 - 134217736 fail to write, but smaller and larger lengths work.


If I change the data type (falsely) to some other 4-byte type during H5Dwrite, e.g. H5T_IEEE_F32LE it does not crash. It also fails with the above error when taking H5T_STD_I32LE (which is same size as my native int on the system).

If I set both H5Dcreate and H5Dwrite to H5T_IEEE_F32LE it also fails with the above error.


As we debugged further, the error resides somewhere at the boundary of H5S_MAX_MPI_COUNT when switching from native MPI-IO types to the struct type that contains main data + leftovers in H5Smpio.c in function H5S_mpio_all_type. As a note, for ints that boundary lies inside the multiple of an int.

The error seems to be thrown on the write of that struct.


Since I can’t report this in JIRA myself: reporters are Axel Huebl and René Widera, both affiliated with HZDR. Just to credit properly since I entered this in my name here.


Hi Axel (and René),

I entered bug HDFFV-10638 for this issue.

Thank you!