Mirror contents of one disk to another

[iMarty]

Hi,

Just bought my first Mac and looking for some advice how to handle a back up of my data drive.

In Windows land, I had a 2TB internal HDD that was mirrored to a 2TB external HDD using the robocopy /MIR command in a batch file. After the initial sync, subsequent runs would only copy new files and make changes to existing ones if applicable. I didn't run this on an automated schedule, just manually as and when significant changes were made, generally a weekly basis.

Is there an equivalent command that can be run in OS X to mirror contents of one volume to another? I've seen some apps that seem to do what I require, but not sure if they're any good.

Any recommendations would be appreciated.

Thanks

iMarty

 

[Bruno09]

Hi,

take a look at... Time Machine.

This will not "mirror" your internal but might suits your needs though.

http://support.apple.com/en-us/HT201250

 

[iMarty]

Thanks for the reply Bruno.

I had looked at Time Machine, but it doesn't seem do what I was doing with the robocopy command in Windows. I'm not wanting to keep incremental daily, weekly, monthly backups etc.

I should clarify that both of the 2TB drives I was using are now external to my Mac. The internal 2TB is now in a caddy and I intend to keep that permanently attached to my Mac Mini. Both drives are USB 3.

 

[Bruno09]

You might use Carbon Copy Cloner to clone or sync drives or folders.

You can use it manually or schedule backups or syncing.

Or use rsync if this is your cup of tea
http://www.maclife.com/article/howtos/using_rsync_keep_your_files_sync_0

 

[Alrescha]

The command you would issue in OS X would be "rsync". It has seemingly infinite switches to control its behavior, and I recommend reading the man page. That said, the following will backup your home directory (for instance) to an external drive:

rsync -avP /Users/youraccountshortname /Volumes/yourexternaldrivename

Subsequent invocations will perform an incremental backup. Some caveats:

1) Time Machine (as suggested) would do a better job of it. You can turn Time Machine on and do a backup and then turn it back off.
2) You need addition switches if you want to backup things like extended attributes (file tags, comments, etc).
3) The supplied rsync command is getting a bit dated. There are free (BackupList) and pay-for (Carbon Copy Cloner) programs which bring their own newer versions of rsync.
4) If you want a true (bootable) mirror, then you want Carbon Copy Cloner.

A.

 

[iMarty]

Thanks for the response Alrescha.

I'll give the trial of Carbon Copy Cloner a go as you and Bruno have suggested.

Thankfully I have some more expendable lower capacity drives that can be guinea pigs