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Often I find myself shuffling large directories (20gb+) of data between computers or drives. What is the most reliable way to ensure that all data is being exactly mirrored with permissions/dates intact?

Bonus points if it's wrapped in a GUI rather than a terminal command.

I saw this question regarding copy utilities for OS X, however the answers were skewed towards speed. My concern is ultimately file/data integrity.

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Rsync has proven to be very stable and effective throughout its years of Unix service. It’s included in any OSX since Tiger and it’s relatively easy to use.

If you want the bonus of a GUI, you can use Arrsync, a free utility better described as:

A Mac OS X graphical front end for the utility rsync.

If, on the other hand you want something more “easy to use” I can recommend you take a look at the two winners:

SuperDuper! ($)

Carbon Copy Cloner (Free, Donationware).

Either will allow you to clone entire drives or folders or anything you can imagine.

Their reliability to copy permissions, ACLs, and that stuff has been proven throughout the years.

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++ for rsync and/or Carbon Copy Cloner. I use both in different situations, and they're definitely the way to go for ensuring data integrity on copy. – Robert S Ciaccio Dec 3 '10 at 16:35
@Martin: nice find on arrsync... I'll have to check that out. rsync is awesome but it has a ridiculous amount of options which can become quite overwhelming if you're a casual user. – Robert S Ciaccio Dec 3 '10 at 16:37
Thanks - I use (and own) SuperDuper, but I double checked and it will only copy full disks/images, not individual folders. I've already started using Arrsync, which seems pretty good. – Josh Newman Dec 3 '10 at 18:06
@3rdParty SuperDuper (and CCC) can be configured to only copy a single folder if that’s your desire. It’s a little bit weird because you have to use the included scripts and add/remove the folders you don’t want to. Check SuperDuper forums and you’ll find plenty of examples. – Martín Marconcini Dec 3 '10 at 20:47
@Martin - thanks! Will do. For now I think arrsync will do the trick. Cheers – Josh Newman Dec 3 '10 at 22:18

As an alternative to CCC or rsync, you could check out ChronoSync; I've been using it for years and it's just rock-solid.

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