So Time Machine requires you to format your external HD to use it.

Discussion in 'macOS' started by lateralus1082, Oct 25, 2007.

  1. lateralus1082 macrumors member

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    Nov 11, 2006
    #1
    Maybe I should have partitioned the thing when I got it :eek:
     
  2. canyonblue737 macrumors 6502a

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    Jan 10, 2005
    #2
    It has to be HFS+ and most out of the box are FAT32 for Windows.
     
  3. CANEHDN macrumors 6502a

    CANEHDN

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    Eagle Mountain, UT
    #3
    So is ZFS not used in Leopard as of yet? If I can, I'll use ZFS. But yes, you probably will need to reformat it.
     
  4. lateralus1082 thread starter macrumors member

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    Nov 11, 2006
    #4
    well, that's a no go. I need this external with my Windows partition :eek:
     
  5. VoodooDaddy macrumors 65816

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    May 14, 2003
    #5
    Im curious about something, for your situation. Is it possible to partition a drive in half, leave 1 partition fat32 but format the other HFS? If so, you could move everything off that drive onto your main drive (provided you have enough free space), partition the external drive in two, format one side fat32 and the other HFS for TM.
     
  6. gadgetgirl85 macrumors 68040

    gadgetgirl85

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    Mar 24, 2006
    #6
    I would like to know this as well
     
  7. torpy macrumors regular

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    Sydney + Los Angeles
    #7
    There's no reason why this shouldn't be possible. Just make sure you do the formatting/partitioning in Disk Utility :)
     
  8. whiteyanderson macrumors 6502

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    Hollywood, California
    #8
    should work as the OS would see each partition as a seperate drive and you just pick the one you want to back up to. unless it has a built in size limitation (requirement) which would suck.
     
  9. cmaier macrumors G3

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    Jul 25, 2007
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    California
    #9
    It seems to support networked AFP shares. I'll have to give it a try with one of my Infrant NAS boxes.
     
  10. vansouza macrumors 68000

    vansouza

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    #10
    should work

    I understand that TM puts its files in a folder.
     
  11. SamIchi macrumors 68030

    SamIchi

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    Aug 1, 2004
    #11
    Yay, Mines HFS+, atleast that's what it says in my system profiler. Does this mean I'm good to go with TM?
     
  12. Doctor Q Administrator

    Doctor Q

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    Los Angeles
    #12
    Why it needs the right formatting

    Time Machine uses a Unix-style filesystem because of the filesystem feature called "hard links." Using hard links, it can keep multiple snapshots of your files without having to store a file multiple times if it hasn't changed. Only a single copy of a given version of a given file is stored. If the file hasn't changed when a new snapshot is taken, Time Machine stores only a few-byte "hard link" to the original file. So the design of Time Machine depends on having the correct type of filesystem.
     
  13. zzcoop macrumors member

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    Nov 10, 2003
    #13
    So, a stupid question (I ask because I've seen a lot of conflicting info on TM's "picky" nature)… if I want to use TM to backup to a 2-disk RAID 1 array, will it be mirrored correctly?

    I assume as much, and have no reason not to expect it to work, but assuming has gotten me into trouble before.

    Another question… if I delete a file from my primary HD that I no longer want TM to keep archived, would going back to the very first instance of the file via TM and deleting it remove it from all successive backups? Or is that not how teh hardlinking works.
     
  14. Transeau macrumors 6502a

    Transeau

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    Jan 18, 2005
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    Alta Loma, CA
    #14
    ZFS is included as Read-Only. Developers have access to Read-Write, but Time Machine does not support it. Also, even if you get Read-Write support, there is no GUI for partitioning / initializing a ZFS, and it's pretty complicated to do it on the command line.
     
  15. Doctor Q Administrator

    Doctor Q

    Staff Member

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    #15
    Erasing the oldest copy on the backup disk would not remove it from successive backups. When you delete one hard linked file, the others remain.

    More gory details: The data of the file is stored in one place on the hard drive. The directory information (primariliy the path, filename, and a pointer to the data's location) is stored once for each hard link. There really isn't a primary copy and secondary copies; they are all equal -- one file known by multiple names or under multiple paths. The filesystem keeps track of the number of hard links to the file's data. As long as any hard links remain, the data is retained. If you delete the very last remaining hard link to the file, the file's data is finally freed (although it may not actually be overwritten until other data is stored on the drive and happens to land in the same place).

    Therefore, to remove all copies of a file, you'd have to find all copies on the backup disk and delete them all. I have yet to confirm this, but I think you won't actually find the file in every snapshot, because if nothing in its enclosing folder has changed between snapshots, only the folder will be hard-linked, not the individual files.

    Be sure to read the Time Machine FAQ for lots of other information about Time Machine.
     
  16. w0ngbr4d macrumors regular

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    Jan 10, 2006
    Location:
    Findlay, OH
    #16
    I'm interested to see how this turns out. I thought the website read that it has to be a network share on another Mac running Leopard. If this works with a NAS system, that would make me very happy since I'm in the market right now.

    Let me know how it goes.

    Thanks.
     
  17. zzcoop macrumors member

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    Nov 10, 2003
  18. byakuya macrumors 6502a

    byakuya

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    Jul 26, 2007
    #18
    it is possible...I have the exact same setup you described because I have to use windows occasionally and all my friends use pcs.

    byakuya
     

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