Content-Addressable Data Synchronization Tool
Contributions from: Daniel Mack, Djalal Harouni, Lennart Poettering, Martin Pitt, Nikita Puzyryov, Thomas Hindoe Paaboel Andersen, Zbigniew Jędrzejewski-Szmek
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