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DBCAST(1)			  mpiFileUtils			       DBCAST(1)

NAME
     dbcast - distributed broadcast

SYNOPSIS
     dbcast [OPTION] SRC DEST

DESCRIPTION
     Parallel MPI application to broadcast a single file from a global file sys-
     tem to node-local storage, like ramdisk or an SSD.

     The  file	is  logically  sliced into chunks and collectively copied from a
     global file system to node-local storage. The bytes of the source file  are
     read  from  the  global file system once and the data are forwarded through
     MPI to be written to storage on all compute nodes.   The  source  file  SRC
     must be readable by all MPI processes.  The destination file DEST should be
     the full path of the file in node-local storage. If needed, parent directo-
     ries for the destination file will be created as part of the broadcast.

     In  the  current implementation, dbcast requires at least two MPI processes
     per compute node, and all compute nodes must run an  equal  number  of  MPI
     processes.

OPTIONS
     -s, --size SIZE
	    The  chunk size in bytes used to segment files during the broadcast.
	    Units like "MB" and "GB" should be	immediately  follow  the  number
	    without spaces (ex. 2MB). The default size is 1MB. It is recommended
	    to use the stripe size of a file if this is known.

     -h, --help
	    Print the command usage, and the list of options available.

EXAMPLES
     1. To broadcast a file to /ssd on each node:

     mpirun -np 128 dbcast /global/path/to/filenane /ssd/filename

     2. Same thing, but slicing at 10MB chunks:

     mpirun -np 128 dbcast -s 10MB /global/path/to/filenane /ssd/filename

     3. To read the current striping parameters of a file on Lustre:

     lfs getstripe /global/path/to/filename

SEE ALSO
     The  mpiFileUtils	source code and all documentation may be downloaded from
     <https://github.com/hpc/mpifileutils>

AUTHOR
     HPC

COPYRIGHT
     2022, LLNL/LANL/UT-Battelle/DDN

0.12				  Jan 29, 2025			       DBCAST(1)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=dbcast&sektion=1&manpath=FreeBSD+Ports+15.1.quarterly>

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