Is exFAT less efficient at utilising disk space than HFS+?

Question

I'm using rsync to copy all files from one 3TB external disk formatted HFS+ to another 3TB external disk formatted exFAT.

I've double checked both disks are exactly the same size and formatted the destination disk right before I began the copy, and in fact the source disk has 38GB space, so there's about 2962 GB of files (1TB = 1000GB on my system).

Rsync has failed around 90% of the way through having filled up the destination disk. Can this be explained by differences between HFS+ and exFAT? Is exFAT much more wasteful of disk space when storing files compared to HFS+?

Answer 1

> much more wasteful of disk space - there will always be differences in efficiency between filesystems. And this will inevitably show as you get closer to maximum capacity of similarly sized disks.

Just a difference on allocation block size will make a huge impact, e.g. lesser efficiency when you have a lot of small files and a comparatively large allocation block size.