Not sure whether Finder effectively uses 'ditto' or not to the the hard work, but using 'ditto' isn't much better than using the Finder. The specific reason for this, and why Finder is also probably slow, is that 'ditto' will by default use something called the 'Mac OS X Unified Buffer Cache'. From my experience this just slows it down when used on lots of large files. One is better turning it off. Thus, use:

  ditto --nocache ...

The documentation from manual page for this option is:

     --nocache     do not perform copies using the Mac OS X Unified Buffer
                   Cache. Files read and written will not be cached, although
                   if the file is already present in the cache, the cached
                   information will be used.

I found the same issue when wanting to copy a few hundred GBs worth of iMove files from one firewire drive to another. Didn't trust 'cp' because of resource fork issue.

[ Reply to This | # ]