Can Time Machine back up an external drive?

Discussion in 'Mac Basics and Help' started by sananda, Feb 12, 2008.

  1. sananda macrumors 68020

    May 24, 2007
    if i have an external drive attached to my mac, can time machine back up both this drive and the internal drive to another external drive?
  2. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    Yes, unless either (1) you place the external drive on TM's "do not backup" list or (2) that external drive is already being used as a Time Machine backup drive (TM will not backup itself)

    But be warned. The time machine drives needs to be large enough to hold everything you need to backup (duh) So in my case I have a 240GB internal drive and a 500GB external drive. I need at least a 750GB Time machine drive and preferably a 1TB drive so I can have multiple versions of my stuff. Very quickly I'll be needing to go with a RAID for my Time machine drive.
  3. sananda thread starter macrumors 68020

    May 24, 2007
  4. tequilaparis macrumors newbie

    Aug 8, 2008
    External drive connected to Time Capsule

    Do you know if this ALSO can be done if the External drive is connected to your Time Capsule?
    That is: Back up from External HD connected to a Time Capsule => Time Capsule?

    Thanks for your help
  5. gusious macrumors 65816


    Dec 2, 2007
    Never done it but i think it can be done!:)
  6. tequilaparis macrumors newbie

    Aug 8, 2008

    Hi, do you have any ideas? I tried yesterday using :
    defaults write TMShowUnsupportedNetworkVolumes 1

    but it did not work, I could not see my External drives on the Time Machine preference panel :(

    All suggestions are welcomed
  7. gusious macrumors 65816


    Dec 2, 2007
    Sorry,i'm confused...You want to backup your external drive or backup everything somewhere?
  8. tequilaparis macrumors newbie

    Aug 8, 2008
    Hi, I would like to backup my External Hard Drive into my Time Capsule, using Time Machine. My external drive is connected directly to my Time Capsule.
  9. bombtrack macrumors member

    Nov 13, 2007
    I have the same question, sort of. I have a 1TB external plugged in via USB to my 1TB Time Capsule. My original plan was to store all my music, etc on the external drive and use the TC as the Time Machine backup. Unfortunately, the only way I can get Time Machine to back up the external drive is to plug it into my Macbook, therefore negating my whole plan.

    I have a large music collection (350GB) so any move I do with my music files takes forever. Now I am pondering using the TC as the main drive and using the external as the TM storage ... I'm pretty sure that will work. Also, iTunes seems to reset the file path to my music files frequently and it takes an hour or two for the "updating itunes library" thing to run its course.

    Any advice on these issues is appreciated.
  10. MSwanberg macrumors newbie

    Nov 14, 2008
    I have a similar problem. The way I answered it is to set up a symbolic link for my Music folder to point to the External drive. Now, when iTunes loses it's mind and goes back to the "default" music location, it's a symbolic pointing to the external drive. iTunes won't change that location, just it's internal pointer to that location. So in essence, I am using the default location; the OS just points that to an alternate location.

    But I also have the Time Machine problem. My external music drive is a 500GB drive and then I have a 1TB external drive acting as my Time Machine backup. Well, the 500GB is showing in the "do not back these up" part of the Time Machine prefs and I can't remove it. As well, Time Machine backs up the symbolic, but doesn't follow the link to backup what's there.

    The result: My Mac Mini's pitiful 40GB drive is being backed up to a 1TB external drive (severe overkill, that) and my music (and movies and podcasts and TV shows) on my 500GB drive are swinging in the wind, just waiting to disappear when that drive dies.

    So, does anyone know how I can get Time Machine to follow the symbolic link and back up my external "Music Folder"? Or does anyone know how I can force Time Machine to let me remove the external drive from its "Do not back this up" list?

    So far, I am running a CRON script to RSYNC the whole 500GB drive to a 1TB NAS, but that's hardly the solution I desire. Time Machine is so convenient.


    New info: check out It just may help (I'll try it when I get home).
  11. musedoasis macrumors newbie

    Aug 31, 2011

    I'm trying to do the same thing. I THINK you have to split your 1 TB into 2 different partitions. One for your internal. One for your external. Do i know how to do that? no. lol

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