Backup Strategy for Carbon Copy Cloner

Discussion in 'OS X El Capitan (10.11)' started by komatsu, Feb 8, 2017.

  1. komatsu macrumors 6502

    Sep 19, 2010
    Backup Strategy for Carbon Copy Cloner

    Ok, you perform a backup with Carbon Copy Cloner (or Super Duper)

    Then next week, you back up again? But after a few more weeks. The disk will probably fill up to capacity?

    What strategy do you recommend?
  2. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    It depends on how you have CCC's Safetynet feature configured. If you have it off (that's what I use) it will just straight up clone the internal to the external, and anything on the external that is not now on the internal will be erased, so the drive will not fill up. If you have Safetynet on, then modified and deleted files will be moved off to a separate folder on the external drive and saved, and over a long enough period of time the drive will start to fill up. There is a Safetynet Pruning feature you configure to start purging that old data when the drive reaches a certain point.

    IMO CCC is more of a clone tool and not that great for keeping versions of files with that Safetynet feature. I use Time Machine for backups and versioning, then CCC for a straight clone without Safetynet. I also use an online backup for my Users folder.

    Attached Files:

  3. komatsu thread starter macrumors 6502

    Sep 19, 2010
    Thanks WB for explanation and a picture does paint a thousand words.

    How does Time Machine handle old backups?
  4. Fishrrman macrumors G5


    Feb 20, 2009
    komatsu wrote:
    "Then next week, you back up again? But after a few more weeks. The disk will probably fill up to capacity?"

    You have it 180 degrees backwards.

    Neither CCC nor SD will "fill up a drive" the way that Time Machine does.
    Quite the contrary, both will keep a backup drive at a manageable size for a LONG time.

    The best strategy for CCC (or SD) is to do incremental backups quite often.

    During an incremental backup, CCC (or SD) will examine the source drive vs. the target, and then copy ONLY THE CHANGED FILES, REPLACING the old versions (of the changed files) on the target drive. The older file gets deleted leaving only the newer version.

    Do it this way, and the backup drive will never occupy "more space" than does the size of the source drive.

    Be aware that you can use CCC to "archive" older versions of files. When you do this, old files WILL NOT be replaced by the newer version, but moved into an archive folder.

    I don't use this feature myself. Seldom (almost never) have I wished I had kept an earlier version of a file around. I want the file "as last used" by me.

    I do a CCC clone of every partition I use once a week.
    For my "main" partition (that contains my critical data), I'll also do a backup when anything major has changed.
    CCC's incremental backup completes in about 30 seconds or so...

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