systemd/casync v2

casync 2

on GitHub

• casync now supports retrieving index and chunk data from sftp:// URLs. (In
  addition to the existing ftp://, http:// and https:// support).

• casync will now honour $TMP if it is set, for placing temporary files and
  directories.

• casync now saves/restores basic btrfs subvolume information. (Specifically it
  will store whether a directory is a subvolume, and whether it has the
  read-only bit set.) Control this metadata option with the new
  --with=subvolume/--without=subvolume and
  --with=subvolume-ro/--without=subvolume-ro switches.

• casync now saves/restores SELinux label information. Control this metadata
  option with the new --with=selinux/--without=selinux switches.

• The libgcrypt dependency has been replaced with an OpenSSL dependency, as
  that appears to be better supported today, and may be used to generate
  SHA512/256 hashes (see below).

• casync now permits selecting the hash function to use with the new --digest=
  option. SHA512/256 is now supported in addition to the old SHA256 algorithm,
  which continues to be supported. The new default however is SHA512/256, as it
  is substantially faster at otherwise equal properties on today's 64bit
  processors. In specific environments SHA256 might perform better, hence both
  algorithms remain supported. Index files contain information about the hash
  algorithm used, hence automatic compatibility is retained.

• casync now permits selecting the compression format to use with the new
  option --compression=. In addition to the originally reported xz compression,
  gzip and zstd compression are now supported, the latter being the new default
  as it provides excellent compression at very high speeds. It's OK to mix
  chunks compressed with different algorithms in the same store, but of course
  clients downloading them need to be new enough to read chunks in non-xz
  formats. Note that the file suffix for compressed chunks changed ".xz" →
  ".cacnk", as they now may contain either compression, and continuing to use
  the ".xz" suffix would be misleading. To retain compatibility with older
  casync, the environment variable $CASYNC_COMPRESSED_CHUNK_SUFFIX may be set
  to ".xz", to force usage of the old suffix.

• When extracting archives or archive indexes a subset of the metadata stored
  in the archive may now be selected to be replayed, using the usual --with=
  and --without= options. For example, if an archive containing full metadata
  is extracted with --without=privileged only the unprivileged metadata fields
  are extracted (i.e. no file ownership, ACLs, SELinux labels, ...).

• After completing an operation statistics about downloaded chunks are now
  shown.

• When invoking "casync mkdev" the third parameter may now be an arbitrarily
  selected path below /dev which is then created as a symlink to the block
  device used, and registered with udev. This means the usual device
  enumeration will find the block device under the name picked. Example:

      # casync mkdev /somepath/tomy/index-file.caibx /dev/quux
  

  This will expose the block image /somepath/tomy/index-file.caibx as /dev/quux.

Contributions from: David Guibert, enkore, Felipe Sateler, Jesus Rodriguez,
John Paul Adrian Glaubitz, Lennart Poettering, Martin Pitt, Silvio Fricke,
Zbigniew Jędrzejewski-Szmek