Time Machine backup query

Discussion in 'iMac' started by Senior Moments, Jul 29, 2013.

  1. Senior Moments macrumors newbie

    Jul 29, 2013
    New to iMac and just getting to grips with the whole kit (having been a DOS and MS Windows person since time began). :eek:

    Have set a 1TB external HD to act as Time Machine. I see that when Time Machine gets towards its full capacity it cleverly deletes old files. Despite reading though many of the FAQs etc I can't seem to find an answer to what I hope is not too stupid a question.

    Are any unique files deleted?

    What I mean is - will at least one copy of every file always be there - regardless of the length of time since it was last accessed or modified? So - in X number of years, when the drive fills and starts to auto delete will I still have available what was on the very first backup?

    Maybe it is a stupid question - I'm sure if really old stuff was likely to drop off there'd be some sort of warning!
  2. noisycats macrumors 6502a


    Jun 1, 2010
    The 'ham. Alabama.

    Eventually, an old file that made the back-up to TM, but that you at some point deleted off your main HD, will be erased. TM gives you a nice buffer, in my case about a year and a half, but it does not perpetually archive (depending on size).

    Two caveats...
    My TM will tell me when it has reached it's max capacity and that it is about to delete an old back-up; no surprises.
    You can always use a larger HD for your TM that allows back-ups to be retained longer.
  3. marzer macrumors 65816


    Nov 14, 2009
    No. If you delete a file from your primary drive, eventually it will disappear from your backups as room is made for backing up existing files. This is how ALL conventional backup systems work that perform incremental snapshots. If not, over time your backups could grow too large to manage conveniently, eventually running out of space for fresh updates in order to hold on to stale data.

    What I would recommend is you buy as large an external backup as you can afford. At least twice the size of your primary drive if not larger. This will allow old, deleted files to be kept for a longer period before TM has to remove them to make room for fresher data.

    If you have important data that needs to be maintained indefinitely, even after removing it from your primary drive, you should consider a long-term archival process.
  4. Senior Moments thread starter macrumors newbie

    Jul 29, 2013
    Thanks good people!

    Thanks for making it so simple to understand. I understand now. Why can't the 'official' FAQs and techy pages be written in such a style?

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