Thunderbolt display with USB external drive

Discussion in 'Mac Accessories' started by iphoneuserinyyz, Nov 29, 2011.

  1. iphoneuserinyyz macrumors member

    Oct 11, 2011
    I about to make a switch from Windows to Mac, and I am still learning, so I apologize if this question is really elementary....

    I will be getting a Thunderbolt display to use with my MBP (and my wife's MBA) when I am working at home. Until I can come up with the money for a NAS (all these Apple purchases at the same time have tapped me out!), I would like to leave an external USB hard drive plugged into the Thunderbolt display (for backup and file sharing).

    My question: when I unplug my laptop from the display, do I need to dismount/eject the external drive first? If so, what would happen if I forgot and just disconnected with the computer still powered on?

    Any help would be appreciated.
  2. MiamiC70 macrumors regular

    Oct 16, 2011
    I am a LONG time windows user and yes you have to unmount it and it is a PITA to do that each time. :mad:
    I cannot fathom why OSX does not auto unmount like Windows does.
    This is my #1 pet peeve vs OSX.
  3. iphoneuserinyyz thread starter macrumors member

    Oct 11, 2011
    Thanks for the response. What is the worst case scenario if I don't unmount first? Drive corruption?
  4. robbieduncan Moderator emeritus


    Jul 24, 2002
    Data corruption certainly. The reason you have to unmount is that the OS does not guarantee to write changes to the disk immediately, rather it optimises writes for performance. If you just yank the disk out it may still be writing to the disk leaving files in a non-usable state. Worst case it was updating some of the files that form critical parts of the file system and you loose all the data.
  5. jsolares macrumors 6502a

    Aug 8, 2011
    Land of eternal Spring
    are you sure windows auto unmounts? if i remove a usb stick from 7 it says i should unmount it first
  6. iphoneuserinyyz thread starter macrumors member

    Oct 11, 2011
    Hmm. Sounds like I should try to figure out a way to buy the NAS sooner rather than later. I am quite certain my wife will not remember to dismount the drives before undocking. Any problems disconnecting from the Thunderbolt display with a NAS (does the NAS need to be dismounted from the macbook first)?

    I suppose if the computer is put into sleep mode (or turned off completely) before disconnecting, this would not be an issue?
  7. MisterMe macrumors G4


    Jul 17, 2002
    Which version of Windows is that? I have dabbled with Windows just about since there was a Windows and I have never seen it auto dismount a volume. In my experience, Windows will likely take longer to write to a removable volume than MacOS/MacOS X. Removing a volume before dismounting it is therefore more likely to cause file damage in Windows than in MacOS/MacOS X.
  8. drsox macrumors 65816


    Apr 29, 2011
    Here's a better approach to mass data storage with a NAS - don't use USB but use a LAN based NAS.
    With a LAN based NAS connection is via AFP or CIFS and nothing needs to be yanked.
    Most new NAS units are GBLAN enabled, as is the TBD, so data rates can be high.

    I've been a LAN NAS user for years with Win and it works just as well with OSX.
    I too have just moved from W to O with a MBA and soon to be a TBD also.
  9. iphoneuserinyyz thread starter macrumors member

    Oct 11, 2011
    That is definitely my long term plan. But I just dropped a bundle on the MBP, MBA, and TBD, so I have to make due for a little while and let the coffers be replenished...

    Does the LAN-based NAS need to be dismounted (from Finder on the laptop) before disconnecting the thunderbolt cable from the laptop (with the laptop on)?
  10. drsox macrumors 65816


    Apr 29, 2011
    I don't think so. I have a LAN based NAS now and I'm using it for a mapped folder within a Win7 installation in Parallels.
    I just turn the MBA off or let it sleep. The NAS is also on a timer, so just isn't there between 12pm and 7am.

    There also would be a mode where the NAS is connected to the TBD not to the MBA - using the TBDs GBLAN. This might buffer the MBA from the NAS wrt dismounting - but I'm no expert in this.

    It also depends on the NAS AFP or CIFS settings as to whether writes are cached or not so the issue of failed data writes may not be relevent. I've been using this for years on WinXp and Win7 without any issues. All my NASs are from Netgear/Infrant - the ReadyNAS range.
  11. Lennyvalentin macrumors 65816


    Apr 25, 2011
    Put the computer to sleep first before you unplug it and wait for the power LED to start pulsing before pulling the thunderbolt cord, if you can't be bothered to eject the disk manually. :) Most assuredly, OSX will flush all disk buffers before entering sleep mode.

    It'll still whine at you for not dismounting the drive most likely, but it shouldn't wreck anything. In any case, OSes don't keep files unwritten in RAM for longer than absolutely necessary since it's so dangerous. In case the computer was to experience a loss of power your data would be gone if it sat stored in RAM for very long.

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