Drawbacks of FAT32?

I’ve seen mentioned that FAT32 has some drawbacks with restic; can anyone shed some light on what these drawbacks might be?

I’m currently using a FAT32 external drive to backup my home folder locally, which I want to then upload to B2 with rclone.

Thanks :slight_smile:

I don’t think they meant that FAT32 has drawbacks with restic specifically, just it has drawbacks in general. For example:

  • No support for file ownership/permissions.
  • Files cannot exceed 4GB in size.
  • Volumes cannot exceed 2TB in size.
  • The filesystem is encumbered by patents, and unlicensed implementations may be vulnerable to lawsuits.
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Awesome, thanks!

I have decided I’m gonna take the legal risk.

I don’t think restic itself will mind either way, but you may see better performance with exFAT. Plus it supports larger volume sizes. I currently have a 5TB exFAT external that I back up to using restic.

Cool, yeah so far so good with FAT32.

I chose FAT32 over exFAT for compatibility reasons (exFAT doesn’t have a good FUSE client for Unix). Also I think 2TB seems to be the sweet spot for HDDs, moneywise (maybe because of the persistence of FAT32?).

This is what I use on Linux. I imagine it would work with Unix. If you’re interested: https://github.com/relan/exfat

Hmm and when I do the “price per gigabyte” equation, 6-8TB is typically the sweet spot as of late lol

I mean when considering drive failure of cost of replacement, e.g. replacing failed 8TB compared to failed 2TB, assuming equal chance of drive capacity failure*, the chance of 1 x 8TB failure > 4 x 2TB failure.

* maybe an old wives tale, but I still believe higher capacity drives fail more often.

Higher capacity drives might fail more often, but your current comparison would require that the 8TB drive is 8 times more likely to fail than one 2TB drive for your comparison to be true (if I did my math right). I’m not sure I buy that.

Hmm I gotta disagree with your math there… say all drives, regardless of capacity, have a 2% chance of failing in a year, so with 1 x 8TB you have a 2% chance of losing 8TB from a single drive failure, whereas with 4 x 2TB you have a 0.5% chance of losing all 8TB (i.e. 2% chance of losing 2TB from a single drive failure, 1% chance of 2 drive failure losing 4TB, and 0.5% chance of all 4 drives failing).

But also, chance is a funny unfalsifiable thing :upside_down_face:

I assumed we were talking about a RAID0 setup of the 4x2TB disks, in which case a single drive failure would still lose all 8TB. “8x” was a bit off on my part; after 3 years the single disk would have an 83% chance of surviving, vs. 47% with 4 disks (assuming equal component failure rate).

I guess it would be best if you could clarify the drive configuration and the intended use case / workflow.

Ah I didn’t even think of RAID… I just have various external HDDs lying around my desk.