Since you're on the same machine - cpio might be your friend.
Run this as root:
cd <sourcedirectory>
find . | cpio -pdmvu <destdirectory>
ex: sourcedirectory = /src, destdirectory = /dest
$> cd /src
$> find . | cpio -pdmvu /dest
-- This might run faster than tar - I would suspect that it would.