So as a followup, the flaw in my plan was that fat32/vfat doesn’t grok
users and groups - or their associated permissions. Therefore both
tar emit loads of errors when copying to such a filesystem.
Which is annoying.
Therefore I went the tarfile route. While taring to the device is
tempting, I imagined walking someone over the phone on how to extract
that and then just got frustrated before even having the conversation.
But tar into the vfat fs has its own annoyance. Namely vfat can’t handle
files larger than 4g. Fun. In the end I came up with this:
tar cpf - some dirs | \
pv -ptera -s 1500g | \
split -b 2G -a 3 - /mnt/backups/backup.
Current transferring at 30.6MB/s with an ETA of 14 hours. We’ll see.
The other limit for vfat is number of files per directory. It’s 65k
and this should only make ~750 so that should be fine too.
Wonder what the limit on command line length is on OS X? Should be able
to get around that with xargs though.