Fastest and safest way to copy a massive amount of data
remote sync, rsync
, is a reliable choice for copying large amounts of data. You can prepare the command and perform a dry-run before committing to the copy; add --dry-run
to simulate the copy.
Your final command will be fairly simple:
sudo rsync -vaE --progress /Volumes/SourceName /Volumes/DestinationName
The flags are:
v
increases verbosity.a
applies archive settings to mirror the source files exactly, including symbolic links and permissions.E
copies extended attributes and resource forks (OS X only).--progress
shows progress during the copy.
sudo
, is used to ensure rsync
has appropriate rights to access and read all files on your drive regardless of owner. This also allows rsync
to write the files to the new drive recreating the original owner information.
rsync
is likely the best choice because it can be rerun in case of problems, offers detailed logging, and is as fast as can be while remaining safe.
There are numerous guides for getting the most from rsync
, rsync command examples provides relevant examples. Take care with the trailing slashes; these can make a world of difference if your copy starts with a folder.
Alternative tools include ditto
and cp
. Both are reasonable choices but offer differing syntax.
I originally published this answer on Ask Different.