Software to backup an external hard drive to another external

Discussion in 'Mac Accessories' started by brainwave89, Oct 12, 2011.

  1. brainwave89 macrumors 6502

    Jul 7, 2006
    I have MBP with a 160GB hard drive and I store all of my music and pictures on an external hard drive. The laptop never leaves my desk. What software can you recommend that I can use so I can backup the hard drive with the music and pictures to another external hard drive?

    Many thanks for looking.
  2. yawns, Oct 12, 2011
    Last edited: Oct 12, 2011

    yawns macrumors member

    Oct 12, 2011
    I'm not sure if Time Machine can do this. I'm guessing yes, but I've never used it.

    You can use rsync from the terminal (or run it as a cron job) to backup your drive. It would go something like this:

    rsync -a --delete /thing/to/backup/ /path/to/backup/storage


    rsync -a --delete /Volumes/MEDIA_DRIVE/ /Volumes/BACKUP_DRIVE

    That would create a mirror of MEDIA_DRIVE on BACKUP_DRIVE. The trailing slash after MEDIA_DRIVE and lack of one after BACKUP_DRIVE are important.

    -a means "archive," and tells rsync to maintain file attributes. --delete tells rsync to delete anything on the receiving end that isn't on the sending end. This keeps the drives "sync'd," but it will also destroy anything it deletes. Be careful with that. If you want to test it first (you should), in a terminal you can do:

    rsync -nav --delete --progress /Volumes/MEDIA_DRIVE/ /Volumes/BACKUP_DRIVE

    The -n means, "dry run." rsync won't do anything when that argument is passed. The -v and --progress (those might be redundant here) will show you everything that is (or would) happen. Use this to verify what would get copied, deleted, and so on prior to actually running it.

    rsync is pretty powerful. You can back things up across your local network or the internet. You can be precise about what you want/don't want copied, and how it should handle those things. It might be helpful to check out the man page ("man rsync") before using it.

    Edit: Apparently Time Machine can do this if you just go into its preferences and allow the other external drive to be backed-up.

    However, it seems that TM can only read HFS drives.
  3. CWallace macrumors 603


    Aug 17, 2007
    Seattle, WA
    I have a similar setup with my iMac and I use Carbon Copy Cloner. Free, easy to configure and easy to use.

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