rsync to exFAT USB

Ran into a weird bug trying to rsync my music collection to a USB drive on a Linux box.

mkstemp function not implemented

This blog post has an explanation for the problem; rsync -a wants to set file owner, group, etc and exFAT doesn’t support those filesystem features. And apparently the Linux FUSE driver doesn’t just fail gracefully? Also not clear why it shows up as an error for mkstemp, except I imagine that libc function is also trying to set permissions.

Anyway trying the cargo cult solution which is not to use rsync -a, but instead just the options you really need, which are -rltD.

 rsync  –delete -rltDW –info=progress2

The -W is a bit of lagniappe, it’s supposed to help USB speeds. info=progress2 is a reasonable display for rsyncing 120GB of music files.

I’m seeing roughly 30±10MBytes/sec writing large files, . The destination is a USB 3.0 adapter for an SD Class 10 card. The card promises 80MB/sec reads and “somewhat slower write speeds”, so that seems reasonable.