MacMost Q&A Forum • View All Forum QuestionsAsk a Question

Move Time Machine backups to another disk drive

Hi Gary and all, thanks for the zillions useful information on your website. I’m a PC user willing to switch soon so I’m gathering info before doing the big step.
What happens when a Time Machine backup disk gets full ? Is there a way to connect another (bigger) disk to the Mac then move the current backup to the new disk, let Time Machine use the new disk, and recycle the old disk ?
Or, when switching Time Machine to another disk, it implies restarting a new backup from scratch, which also implies I will loose the whole history of change I made to my files ?
Thanks and keep up the good work !
Alex from Brussels Belgium

Comments: 6 Responses to “Move Time Machine backups to another disk drive”

    9 years ago

    Time Machine will continue to keep incremental backups of each file until you get close to running out of drive space. Then it starts removing older copies of files. It has a system for doing this with a logic behind it. You won’t ever run out of space unless the TM drive is smaller than the drive it is backing up. I recommend at least a drive twice as big as the one you are backing up. But even more if you can.
    If you switch to another TM disk you would just start a new TM backup. That’s the cleanest way to do it. Yes, you would lose your history of files — but TM is a backup solution, not an archiving one. If you really need an old copy of a file you shouldn’t be “storing” it in Time Machine, you should make an archive copy somewhere else. Backup solutions like TM are for emergencies only, like if your drive fails or you accidentally delete or alter a file you didn’t intend to. If you treat TM as a backup, not something it isn’t, then you won’t have a problem.

      Alex from Brussels Belgium
      9 years ago

      Ok thanks for the valuable info.

      Nevertheless I don’t totally agree with you on the purpose of TM. For me it’s clearly more than a simple backup tool, it has archiving abilities as well. Well, at least, that’s how I understood Apple wanted to sell the idea ;-)

      It has both purposes: restore lost data (backup) and “fly through time” to choose the data as it was at any time in the history of a file (archiving).

      Because you don’t need to have lost your file to be able to access another (possibly older) version, you can access the complete history of versions, including the current one. This is typically an archiving purpose.

      Now, archiving implies backup as well.

      So TM maybe lacks the ability of going back through time as far away as “before I changed my TM disk”.

      Apple guys, there is still room for some improvements. I am a developer, I can help if you need… ;-)

      Keep up the good work!

    9 years ago

    I think that is a dangerous way to think of it. You have no guarantee that an old version of any file will be there. I would never use it in the way you suggest and I would never recommend anyone use it that way. I’ve never heard Apple suggest to use TM for archiving. It is simply a better backup system. See episode 512:
    If you really want something like this, and you are a developer, then you should use a versioning tool, not TM, for that purpose.

    Michael Olivero
    9 years ago

    > I’ve never heard Apple suggest to use TM for archiving.
    Thanks for all the feedbacks, however I must with Alex. While the archive is not guaranteed to be there like Gary mentions, it’s nice to have archives when the need occurs to go back. For example, say I keep a monthly total expense income in excel I reset every month. I don’t keep copies or multiple sheets or columns, just a single column. I could quickly go back to the last few months and quick view the end of month totals with little effort. Incidentally, Apple did start recommending revision history and actually made it a built int feature in the iLife applications.

    Vince Aderente
    8 years ago

    Maybe I am missing a point here, but if you disconnect and keep the “old” TM drive, connect a new one and use it for TM, I think you don’t lose anything and you can still retrieve older versions of files or deleted files (accidently or otherwise) by simply re-mounting the older TM drive and recovering the file you want?

      8 years ago

      Probably, yes. But it isn’t the sort of thing you want to count on.

Comments Closed.