I just did some rudimentary benchmarking of various Linux filesystems on Ubuntu 10.10/32 bit, doing an rsync -av of /usr /about 3,5GB of data) to a USB-connected, freshly formatted ATA drive (Seagate Barracuda 750g), here are the results (caveat: I used the system for web browsing and some shell stuff during the runs, so take the numbers with a large grain of salt):

xfs: 10m 1sec

jfs: 9m 5sec

btrfs: 7m 29sec

ext4: 6m 47sec

All filesystems were formatted using default parameters.

If it wasn’t for the long delay creating a largish ext4 fs as it writes its inode tables, I guess I’d be using ext4 more! 😉 Nice work also on btrfs, I guess there’s some more performance to be gained as the file system comes of age.