External storage question??

Discussion in 'Mac Accessories' started by marc55, May 22, 2014.

  1. marc55, May 22, 2014
    Last edited: May 22, 2014

    marc55 macrumors 6502a


    Oct 14, 2011
    I will be getting a rMBP in the near future and also have a PC.

    Both the PC and rMBP have 500GB drives.

    I would like to get a 1TB WD My Passport Air to serve as a back up for both.

    Is 1TB enough for two 500GB backup? I thought I had read somewhere that Time Machine requires double storage capacity?

    So, can the WD be formatted in HFS+ and NTSF? (500GB each), and use Paragon for the rMBP to write to the NTSF Drive.

    Also, with the dual partition, will I be able to back up using Time Machine?

    Thank you
  2. GGJstudios macrumors Westmere


    May 16, 2008
    You can create two partitions on the drive, with a different format for each partition. Also, OS X can be made to read and write to NTFS, just as Windows can be made to read and write to HFS+. Yes, you can use the HFS+ partition for Time Machine backups.

    Format A Hard Drive Using Disk Utility (which is in your /Applications/Utilities folder)
    Choose the appropriate format:
    HFS+ (Hierarchical File System, a.k.a. Mac OS Extended (Journaled) Don't use case-sensitive) NTFS (Windows NT File System)
    • Read/Write NTFS from native Windows.
    • Read only NTFS from native Mac OS X [*]To Read/Write/Format NTFS from Mac OS X, here are some alternatives:
      • For Mac OS X 10.4 or later (32 or 64-bit), install Paragon (approx $20) (Best Choice for Lion and later)
      • For 32-bit Mac OS X, install NTFS-3G for Mac OS X (free) (does not work in 64-bit mode)
      • For 64-bit Snow Leopard, read this: MacFUSE for 64-bit Snow Leopard
      • Some have reported problems using Tuxera (approx $36).
      • Native NTFS support can be enabled in Snow Leopard and Lion, but is not advisable, due to instability.
    • AirPort Extreme (802.11n) and Time Capsule do not support NTFS
    • Maximum file size: 16 TB
    • Maximum volume size: 256TB
    • You can use this format if you routinely share a drive with multiple Windows systems.
    exFAT (FAT64)
    • Supported in Mac OS X only in 10.6.5 or later.
    • Not all Windows versions support exFAT. See disadvantages.
    • exFAT (Extended File Allocation Table)
    • AirPort Extreme (802.11n) and Time Capsule do not support exFAT
    • Maximum file size: 16 EiB
    • Maximum volume size: 64 ZiB
    • You can use this format if it is supported by all computers with which you intend to share the drive. See "disadvantages" for details.
    FAT32 (File Allocation Table)
    • Read/Write FAT32 from both native Windows and native Mac OS X. [*]Maximum file size: 4GB.
    • Maximum volume size: 2TB
    • You can use this format if you share the drive between Mac OS X and Windows computers and have no files larger than 4GB.
  3. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Yes, you can make two partitions... one HFS+ and one NTFS then use Paragon like you described. You would be able to use that same disk to backup your Mac with Time Machine and Windows.

    As far as size it is only indirectly related to drive size. All that really matters is how much actual data you have or expect to have on there. A Time Machine backup drive of 1.5 to 2X the size of the expected amount of data is plenty to allow for saved versions of files.

    So for example, if you have a 3TB drive but only ever expect to have 200GB of data on there, a 350GB to 400GB drive for backups would be fine.

Share This Page