
But xz -9 (as, e.g., used for Linux kernel tarballs) uses much more than bzip -9.
#Tar xz multithreaded archive#
However none of these are relevant for kernel distribution)ġ: In archive size, xz -3 is around bzip -9. Newer versions of xz now have an (optional) block mode which allows data recovery after the point of corruption and parallel compression and decompression.
(There are some specific scenarios where a good bzip2 implementation may be preferable to xz: bzip2 can compresses a file with lots of zeros and genome DNA sequences better than xz. I didn't attempt to replicate the results, and I suspect some of it has changed (mostly, I expect xz has improved, as its the newest.)
I looked at compression comparisons in a blog post. There isn't really a realistic combination of factors that'd get you to pick bzip2.
Want to save download time and/or bandwidth: xz. Need to decompress minimal tools available: gzip. Given, not very likely when talking about kernel sources. Need to decompress on a machine with very limited memory (<32 MB): gzip. So, both gzip and xz format archives are posted, allowing you to pick: It, however-at the compression settings typically used-requires more memory to decompress and is somewhat less widespread. Compatibility (how wide-spread the decompression program is)Ĭompression memory & CPU requirements aren't very important, because you can use a large fast machine for that, and you only have to do it once.Ĭompared to bzip2, xz has a better compression ratio and lower (better) decompression time. Compression ratio (i.e., how small the compressor makes the data). For distributing archives over the Internet, the following things are generally a priority: