The flux dump command writes a KVS snapshot to a portable archive format, usually read by flux-restore(1).

The snapshot source is the primary namespace of the current KVS root by default. If --checkpoint is specified, the snapshot source is the last KVS checkpoint written to the content backing store.

The archive is a file path or - for standard output. If standard output, the format is POSIX ustar with no compression. Otherwise the format is determined by the file extension. The list of valid extensions depends on the version of libarchive(3) used to build Flux, but modern versions support:


POSIX ustar format, compatible with tar(1).

.tgz, .tar.gz

POSIX ustar format, compressed with gzip(1).


POSIX ustar format, compressed with bzip2(1).


POSIX ustar format, compressed with xz(1).


ZIP archive, compatible with unzip(1).


POSIX CPIO format, compatible with cpio(1).


ISO9660 CD image


-h, --help

Summarize available options.

-v, --verbose

List keys on stderr as they are dumped instead of a periodic count of dumped keys.

-q, --quiet

Don't show periodic count of dumped keys on stderr.


Generate snapshot from the latest checkpoint written to the content backing store, instead of from the current KVS root.


Bypass the broker content cache and interact directly with the backing store. This may be slightly faster, depending on how frequently the same content blobs are referenced by multiple keys.


KVS commits are atomic and propagate to the root of the namespace. Because of this, when flux dump archives a snapshot of a live system, it reflects one point in time, and does not include any changes committed while the dump is in progress.

Since flux dump generates the archive by interacting directly with the content store, the --checkpoint option may be used to dump the most recent state of the KVS when the KVS module is not loaded.

Only regular values and symbolic links are dumped to the archive. Directories are not dumped as independent objects, so empty directories are omitted from the archive.

KVS symbolic links represent the optional namespace component in the target as a NAME:: prefix.

The KVS path separator is converted to the UNIX-compatible slash so that the archive can be unpacked into a file system if desired.

The modification time of files in the archive is set to the time that flux dump is started if dumping the current KVS root, or to the timestamp of the checkpoint if --checkpoint is used.

The owner and group of files in the archive are set to the credentials of the user that ran flux-dump.

The mode of files in the archive is set to 0644.


Flux: http://flux-framework.org

Flux RFC: https://flux-framework.readthedocs.io/projects/flux-rfc


10/Content Storage Service

11/Key Value Store Tree Object Format v1


flux-restore(1), flux-kvs(1)