For my work as a media professional I have been using the rsync frontend arrsync to back up my work, as time machine doesn't have the features I need. Arrsync, however, has not been in development for some time, and I was wondering if anyone knew of a decent alternative.

Specifically I need something with arrsync's "unidirectional merge" function, which basically just adds new files or overwrites old files with newer versions to my backup hard drives. This allows me to remove projects from my computer I don't need immediately in order to save space, but still keeps them in backup. In other words, the function does not simply create a snapshot, but an ever-growing collection of all my past projects.

I also need something with an easy to use and understand UI. I realise I can create custom scripts for rsync, but there are other less computer literate people in my office who rely on this program as well. I have also tried simply copying things across using finder, but this becomes incredibly tedious, even with some of the smarter copying capabilities of OSX, as directory structures can be quite complex.

Sorry this has gotten quite long (I realise I have some frustratingly specific needs!) Does anyone know of a program, be it standalone of as an rsync frontend, that has these functions and is relatively up-to-date? Cheers!

4 Answers 4


I think Carbon Copy Cloner 4 would do the trick here.

Its major selling point is that it creates bootable backups, but it can copy folders with data also.

If I understand right, the equivalent of that Arrsync merge function would be CCC's "SafetyNet" feature, with "Prune archives in the SafetyNet when:" set to Never.

(Edited:) I think the closest equivalent of that Arrsync "unidirectional merge" function would be:

  • use Advanced Settings
  • set "SafetyNet" to "Don't delete anything"
  • set "SafetyNet pruning" to Never.

From http://bombich.com/kb/ccc4/release-notes

Carbon Copy Cloner 4.0.2

... When the "Don't delete anything" Advanced SafetyNet option is specified, older versions of modified items are not deleted, they are moved to the SafetyNet. SafetyNet pruning is now available for tasks configured with this option.

So if I understand right (this will need testing!), this will add new files to the backup, put new versions of changed files into place, and move the out-dated versions to the SafetyNet folder, where you can delete them. I think this achieves an "ever-growing collection of all my past projects".

CCC calls rsync to do the actual work, so it is fast. You might consider it "standalone", though, as it doesn't give access to all rsync options.

I think the UI in the new version 4 is great.

There is a 30-day trial.

  • 1
    As far as I know, CCC doesn't offer an "unidirectional merge" feature (nor access to rsync functionality per se).
    – nohillside
    Sep 30, 2015 at 8:37
  • 1
    @patrix Thanks. I've looked a bit more closely at CCC's options and made some edits to clarify.
    – Ashley
    Sep 30, 2015 at 9:15

I use iBackup for this - currently I use it to clone certain folders to an external drive on a schedule, but I have used it the same way you describe. It's just a gui for rsync and ditto, and has some access to more advanced switches


You gotta check out DropSync!
I think it does exactly what you're looking for.

Also I'd say it sounds like you might need 2 apps.
Maybe use DropSync to do your push/pull syncing of your 'working copy'
then a backup app up to do your backups.
Shameless plug because you said simple UI:
Backaroo does backups:
and Truck is a simple rsync GUI for throwing data around with rsync: http://bonhardcomputing.com/truck/


Try Chronosync - http://econtechnologies.com/chronosync.html

I'm not sure what's under the hood but it's super simple, stable, and works well for your stated needs. I use it in a photography environment where I shoot, say, 1000 photos to an internal drive, sync it to two external drives, then sync as I edit (1000 images becomes 387...)

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