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The exFAT filesystem does not support symlinks.

I'm now faced with the need to backup some directories, which do have symlinks, into an exFAT-formatted drive. For reasons, I cannot change the filesystem type.

I could create a tar or similar archive of all the files, and copy that to the drive, but that means access to individual files or directories will be slow, and "entangle" them in case of some kind of corruption.

What other alternatives do I have for making this kind of backup?

Notes:

  • I use Devuan GNU/Linux, although I'm more interested in platform-inspecific answers.
  • I'm not asking for a recommendation of an app or a utility. If you know of an interesting one, write about how it solves this problem.
einpoklum
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  • A regular file that holds a filesystem that supports symbolic links. Please tell us whether or not this idea is against the reasons. – Kamil Maciorowski Oct 24 '21 at 21:23
  • @KamilMaciorowski: I mentioned the possibility of creating an archive with many files - what you're suggesting is more or less the same, isn't it? – einpoklum Oct 24 '21 at 21:25
  • One of your concerns was slow access. In case of tar the concern is justified because tar needs to examine many headers until it reads the right one. Filesystems don't do this. – Kamil Maciorowski Oct 24 '21 at 22:02
  • @KamilMaciorowski: Fair enough. But another concern is data corruption which may lead to the entire filesystem-in-a-file being lost. Still, perhaps you should make this an answer. – einpoklum Oct 25 '21 at 07:26
  • The purpose of my first comment was to ask you if you can actually use some other filesystem in general. You wrote "for reasons, I cannot change the filesystem type"; the reasons are undisclosed. One of the possible reasons is the OS/device that is going to read the backup can read exFAT only. If this was the case, my idea wouldn't be helpful. That's why I posted it as a comment. Now I understand the idea is not against the reasons. – Kamil Maciorowski Oct 25 '21 at 07:46
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    @KamilMaciorowski: It's a disk which I'm not fully in control of, and it's required that it keep the current filesystem. Your solution is still relevant, since when I read the disk, I can always mount a filesystem from a file. But truth be told, I was hoping for another suggestion. – einpoklum Oct 25 '21 at 09:09
  • rdiff-backup promises a lot. See this link. I quote: "Although some Windows filesystems lack features like FIFOs, case sensitive filenames, or files with colons (":") in them, all of these situations should be autodetected and compensated for by rdiff-backup". This is not an answer because in my tests with an actual exFAT filesystem (mounted with FUSE exfat 1.3.0 in Debian 10) rdiff-backup 1.2.8 throws an error. The tool is written in Python and maybe it can be fixed; but I'm not a programmer, so I'm just leaving this information here. – Kamil Maciorowski Oct 25 '21 at 17:25

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