Parallel MPI application to recursively copy files and directories.

dcp is a file copy tool in the spirit of cp(1) that evenly distributes the work of scanning the directory tree, and copying file data across a large cluster without any centralized state. It is designed for copying files that are located on a distributed parallel file system, and it splits large file copies across multiple processes.


--bufsize SIZE

Set the I/O buffer to be SIZE bytes. Units like "MB" and "GB" may immediately follow the number without spaces (e.g. 8MB). The default bufsize is 4MB.

--chunksize SIZE

Multiple processes copy a large file in parallel by dividing it into chunks. Set chunk to be at minimum SIZE bytes. Units like "MB" and "GB" can immediately follow the number without spaces (e.g. 64MB). The default chunksize is 4MB.

--daos-prefix PREFIX

Specify the DAOS prefix to be used. This is only necessary if copying a subset of a POSIX container in DAOS using a Unified Namespace path.

--daos-api API

Specify the DAOS API to be used. By default, the API is automatically determined based on the container type, where POSIX containers use the DFS API, and all other containers use the DAOS object API. Values must be in {DFS, DAOS}.

-i, --input FILE

Read source list from FILE. FILE must be generated by another tool from the mpiFileUtils suite.

-L, --dereference

Dereference symbolic links and copy the target file or directory that each symbolic link refers to.

-P, --no-dereference

Do not follow symbolic links in source paths. Effectviely allows symbolic links to be copied when the link target is not valid or there is not permission to read the link's target.

-p, --preserve

Preserve permissions, group, timestamps, and extended attributes.

-s, --direct

Use O_DIRECT to avoid caching file data.

-S, --sparse

Create sparse files when possible.

--progress N

Print progress message to stdout approximately every N seconds. The number of seconds must be a non-negative integer. A value of 0 disables progress messages.

-v, --verbose

Run in verbose mode.

-q, --quiet

Run tool silently. No output is printed.

-h, --help

Print a brief message listing the dcp(1) options and usage.


If a long-running copy is interrupted, one should delete the partial copy and run dcp again from the beginning. One may use drm to quickly remove a partial copy of a large directory tree.

To ensure the copy is successful, one should run dcmp after dcp completes to verify the copy, especially if dcp was not run with the -s option.


  1. To copy dir1 as dir2:

mpirun -np 128 dcp /source/dir1 /dest/dir2

  1. To copy contents of dir1 into dir2:

mkdir /dest/dir2 mpirun -np 128 dcp /source/dir1/\* /dest/dir2

  1. To copy while preserving permissions, group, timestamps, and attributes:

mpirun -np 128 dcp -p /source/dir1/ /dest/dir2


Using the -S option for sparse files does not work yet at LLNL. If you try to use it then dcp will default to a normal copy.

The maximum supported file name length for any file transferred is approximately 4068 characters. This may be less than the number of characters that your operating system supports.


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