To mirror a huge tree...

[Ron Johnson <ron.l.johnson@cox.net>]

is it more efficient to use tar, rsync or "cp -r"?

(Yes, I know that incremental backups would be faster with rsync. 
Also, most all of these files are already compressed, so tar or 
rsync -z or -j wouldn't help either.)

With "cp -r" to an ext4 (with extents enabled) fs mounted on an 
external USB hard drive, I'm getting a consistent 30MBps, which is 
half of USB2.0's theoretical 480Mbps.

Thus, could I tweak a statistically significant more MBps using tar 
or rsync?  Pre-fetching files or some such?  As it stands now, 88% 
of my 8GB RAM is "cached".

Or is 30MBps about as good as I can get from the combination of the 
USB software and hardware?

--
Scooty Puff, Sr
The Doom-Bringer