Xz format considered inadequate for long-term archiving (2016)
Correct, xz is no longer particularly useful, mostly annoying.For read-only long-term filesystem-like archives, use squashfs with whatever compression option is convenient.  The cool thing about squashfs is you can efficiently list the contents and extract single files.  This is why it's an ultimate best option for long-term filesystem-esque archives.https://en.m.wikipedia.org/wiki/SquashFSFor everything else, or if you want (very) fast compression/decompression and/or general high-ratio compression, use .zstd.https://github.com/facebook/zstdI've used this combination professionally to great effect. You're welcome :)