On Fri, Apr 3, 2026 at 7:48 AM Tom Lane <[email protected]> wrote: > *This* tar defaults to: > --format=posix -f- -b20 --quoting-style=escape --rmt-command=/usr/bin/rmt > --rsh-command=/usr/bin/ssh
>From some quick googling, OpenSUSE is the only distro I could find that does this, but the fine manual says they plan to make pax the default upstream so eventually it might be everywhere: https://www.gnu.org/software/tar/manual/html_section/Formats.html > Interestingly, pg_verifybackup's t/003_corruption.pl test also fails > with the same issue, so apparently this platform is even more > aggressive about sparse-ifying files than Thomas' FreeBSD box. Looks like sparse files and BTRFS might be a red herring then, if it's simply been told to put a pax header on every file? I think my system might be defaulting to "restricted pax", meaning that pax headers are added to individual files only if necessary, path-too-long etc, magic sparse format triggered, etc. https://man.freebsd.org/cgi/man.cgi?query=libarchive-formats > I'm inclined to push the logic for selecting these tar options > into some common subroutine in Test::Utils, rather than having > two copies (and maybe more later). How about using --format=ustar, instead of that sparse control stuff? That solves the BSD tar + ZFS problem and the OpenSUSE GNU tar default format problem in one fell swoop, and actually says what we want explicitly. Should we have a <note> near the --path/--wal-path documentation to state explicitly that usta format is required, and that pax is not [yet] supported, and that --format=ustar might be required on some systems?
