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[Lzip-bug] Tarlz 0.11 released
Antonio Diaz Diaz
[Lzip-bug] Tarlz 0.11 released
Fri, 15 Feb 2019 13:05:57 +0100
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I am pleased to announce the release of tarlz 0.11.
Tarlz is a massively parallel (multi-threaded) combined implementation
of the tar archiver and the lzip compressor. Tarlz creates, lists and
extracts archives in a simplified posix pax format compressed with lzip,
keeping the alignment between tar members and lzip members. This method
adds an indexed lzip layer on top of the tar archive, making it possible
to decode the archive safely in parallel. The resulting multimember
tar.lz archive is fully backward compatible with standard tar tools like
GNU tar, which treat it like any other tar.lz archive. Tarlz can append
files to the end of such compressed archives.
Tarlz can create tar archives with five levels of compression
granularity; per file, per block (default), per directory, appendable
solid, and solid.
Of course, compressing each file (or each directory) individually can't
achieve a compression ratio as high as compressing solidly the whole tar
archive, but it has the following advantages:
* The resulting multimember tar.lz archive can be decompressed in
parallel, multiplying the decompression speed.
* New members can be appended to the archive (by removing the EOF
member) just like to an uncompressed tar archive.
* It is a safe posix-style backup format. In case of corruption,
tarlz can extract all the undamaged members from the tar.lz
archive, skipping over the damaged members, just like the standard
(uncompressed) tar. Moreover, the option '--keep-damaged' can be
used to recover as much data as possible from each damaged member,
and lziprecover can be used to recover some of the damaged members.
* A multimember tar.lz archive is usually smaller than the
corresponding solidly compressed tar.gz archive, except when
individually compressing files smaller than about 32 KiB.
Note that the posix pax format has a serious flaw. The metadata stored
in pax extended records are not protected by any kind of check sequence.
Because of this, tarlz protects the extended records with a CRC in a way
compatible with standard tar tools.
The homepage is at http://www.nongnu.org/lzip/tarlz.html
An online manual for tarlz can be found at
The sources can be downloaded from
The sha256sum is:
Changes in version 0.11:
* An endless loop happening when trying to list or extract from an
empty tar.lz archive has been fixed.
* Multi-threaded '-c, --create' and '-r, --append' have been implemented.
* The default compression granularity has been changed to '--bsolid'
(per block compression) instead of '--no-solid' (per file compression).
* The message "Removing leading '<prefix>' from member names." is now
shown once for each <prefix>.
* The new chapter 'Minimum archive sizes required for multi-threaded
block compression' has been added to the manual.
Please send bug reports and suggestions to address@hidden
Antonio Diaz, tarlz author and maintainer.
Self-determination is a right, not a crime. Free Catalan political
If you care about long-term archiving, please help me replace xz with
lzip. See http://www.nongnu.org/lzip/lzip_benchmark.html#xz1
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