DBCAST(1)

💖 dbcast(1) — distributed broadcast 💖

okay bestie, this is the DBCAST(1) page from mpiFileUtils, and it’s literally all about dbcast — distributed broadcast. buckle up 🫶

✨ NAME ✨

dbcast — distributed broadcast. that’s the whole vibe 💅

🦋 SYNOPSIS 🦋

dbcast [OPTION] SRC DEST

💅 DESCRIPTION 💅

okay so dbcast is a parallel MPI application that broadcasts a single file from a global file system to node-local storage — think ramdisk or an SSD, bestie. iconic behavior honestly ✨

the file gets 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. no cap, that’s the whole flow 🌈

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 directories for the destination file will be created as part of the broadcast. cute, right? 🎀

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. that part is important, bestie — don’t skip the vibe check 🫶

🎀 OPTIONS 🎀

• -s, --size — the chunk size in bytes used to segment files during the broadcast. units like MB and GB should immediately follow the number with no 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. your little help menu moment 🫶

🔥 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> — go get your read on, bestie 📚✨

🌸 AUTHOR 🌸

HPC — that’s the author credit, periodt 💜

💜 COPYRIGHT 💜

2022, LLNL/LANL/UT-Battelle/DDN — all the legal cuteness preserved 🎀

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💖 mwah! that’s DBCAST(1) from mpiFileUtils, version 0.12, dated Jan 29, 2025 — bye bestie 🫶💅