"If you're not sure what any of this means, our product is Not For You."

Discussion in 'macOS' started by gjarold, Aug 24, 2015.

  1. gjarold macrumors regular

    Joined:
    Nov 14, 2007
    #1
    Saw this on /r/macadmin this morning:

    "If you're not sure what any of this means, our product is Not For You."

    http://www.rsync.net/products/mac.html

    I *do* use rsync and I think I understand what they're saying about the snapshots ... that's basically what Time Machine backups are - snapshots made with hard links.

    I guess I pass the test :)
     
  2. donlab macrumors 6502

    donlab

    Joined:
    Jun 3, 2004
    Location:
    USA
    #2
    Time machine doesn't take snapshots. It backs up the files that changed since the last full. Its like an incremental backup forever strategy.

    Snapshots are different.
     
  3. BrianBaughn macrumors 601

    BrianBaughn

    Joined:
    Feb 13, 2011
    Location:
    Baltimore, Maryland
    #3
    Time Machine takes local "snapshots" when your backup drive isn't available.
     
  4. donlab macrumors 6502

    donlab

    Joined:
    Jun 3, 2004
    Location:
    USA
    #4
    Brian, nice find you brought up another scenario. Time machine local snapshot is used when your time machine external drive isn't available. It is my understanding that both time machine and time machine local snapshot are not truly filesystem snapshots. Apple can say its a "snapshot" but the underlying filesystem HFS+ does not support snapshots. Therefore its really an incremental backup with hard links. RSYNCH is saying that once your files are sync'd to their cloud they snapshot. And they are taking snapshots using filesystem snapshots on ZFS. To some this might be a pedantic explanation but I've really been hoping that apple will one day upgrade/switch to a filesystem that supports snapshots among other things.
     
  5. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #5
    Without getting into semantics about what a snapshot is, what Time Machine (TM) local snapshots does is two things. If you open say an Excel file and make changes to it then save, the old version will be saved in TM local snapshots. Also, anything you put in the trash, then empty is not really emptied, but rather moved to the hidden local snapshots folder. This hidden folder is at /.MobileBackups.
     

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