Time Machine: "Oldest backups are deleted when your disk becomes full."

Discussion in 'Apple' started by Davoud, Apr 26, 2014.

  1. Davoud

    Davoud Guest

    That's fine by me. I'm a backup paranoid after losing a WordStar
    document from my Osborne I in 1982.

    But it appears not to be working. TM says it can't backup because the
    disk is too full. Based on the quote in the title, I expected it would
    delete old backups to make room and go about its business.

    What don't I know?

    Davoud, Apr 26, 2014
    1. Advertisements

  2. Each backup only contains the files that changed since the previous
    backup. The way this is done is that all the filenames for unchanged
    files are hard links to the same file.

    So when a backup is deleted, it only recovers space for the files that
    have newer versions in the next backup. If most of them didn't change,
    deleting the backup won't get you much space. This can easily happen if
    your disk is full of archives of images and movies that you never modify
    or delete -- all backups will be 90% the same stuff.
    Barry Margolin, Apr 26, 2014
    1. Advertisements

  3. Davoud

    David Ritz Guest

    Hash: SHA1

    On Saturday, 26 April 2014 00:59 -0400,
    If you read the fine print, in the notice, it says that the deletion
    will take place, the next time Time Machine runs. I have such a post
    deletion backup running, at this time.

    - --
    David Ritz <>
    Be kind to animals; kiss a shark.

    Version: GnuPG v2.0.22 (Darwin)

    -----END PGP SIGNATURE-----
    David Ritz, Apr 26, 2014
  4. Davoud

    David Empson Guest

    To clarify, there are two possible scenarios and I'm not sure which one
    you are encountering.

    (a) If you are trying to back up a new computer to a drive which is
    already being used for Time Machine backups of other computers, then the
    new backup can only start if there is enough free space. Time Machine
    will only delete old backups from the same computer in order to free up
    space for new backups.

    Note that some instances of computer/drive replacement might result in
    Time Machine thinking it needs to start a new backup rather than
    continuing an existing one. (I encountered this once when I was running
    somewhere around 10.5/10.6, but not when I had a similar situation
    around the 10.8/10.9 timeframe, so Apple may have improved the logic in
    later OS X versions.)

    (b) If nothing out of the ordinary has happened and TM has just reached
    the point where the backup disk is full, then it should be able to work
    as advertised, by deleting the oldest backup (or several old backups) of
    this computer to make room for the next backup.

    If there has been a significant change on the computer, such as adding a
    new large drive or lots of files on an existing drive that need to be
    added to the backup (including moving or renaming a huge folder) this
    can trigger a situation where TM thinks it can't delete enough old
    backups to make room - it needs to be able to retain at least one old
    David Empson, Apr 27, 2014
  5. Davoud

    Tom Stiller Guest

    In this case it may be possible to use the shell command:
    inheritbackup {machine_directory | sparsebundle} ot accquire the old backup.

    I used this technique to "inherit" a backup sparsebundle produced on an
    old MacBook by its replacement.
    Tom Stiller, Apr 27, 2014
  6. Davoud

    Guest Guest

    easily done using the command line utility tmutil in lion and later.

    it's possible to do it in earlier systems but it's a pain in the ass.
    Guest, Apr 27, 2014
  7. Davoud

    Davoud Guest

    David Empson:
    Not the case.
    Not the case.
    That's the case, as far as I know.
    That's my thinking. Simple enough, so I thought. I didn't understand
    Mr. Margolin's explanation at all. It has been working all along.
    Not the case.

    TM just quit working one day. April 24, to be specific.

    I think that I'll erase the TM volume and turn it into a SuperDuper
    backup volume. I've already got one of those for this machine; one more
    can't hurt.

    Thanks for taking time to reply.
    Davoud, Apr 28, 2014
  8. Davoud

    J Burns Guest

    What exactly does it say? Sometimes when the big print says the disk is
    full, the fine print says it isn't because Time Machine deleted some old
    J Burns, Apr 28, 2014
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.