# Connecting a 4TB Drive Via USB or Firewire to a Mac Mini **URL:** \ **Category:** Factual Questions\ **Created:** [September 29, 2008, 7:21pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751 "2008-09-29T19:21:21Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Nobody\_Special](https://avatars.discourse-cdn.com/v4/letter/n/bbce88/32.png) [@Nobody\_Special](https://boards.straightdope.com/u/Nobody_Special)\ **Post date:** [September 29, 2008, 7:21pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/1 "2008-09-29T19:21:21Z")
I recently built a five-drive, RAID 5 server using a [Sans Digital MobileRaid](http://www.sansdigital.com/mobileraid/mr5ct1.html) and five 1TB drives with the intent of connecting them to my Mac Mini over USB (Speed is a low priority). However, I’ve come to learn that bot Firewire and USB are both limited to recognizing a maximum of 2TB. Is there any way around this? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 29, 2008, 7:24pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/2 "2008-09-29T19:24:02Z")
> [@Nobody\_Special](#): > > I recently built a five-drive, RAID 5 server using a [Sans Digital MobileRaid](http://www.sansdigital.com/mobileraid/mr5ct1.html) and five 1TB drives with the intent of connecting them to my Mac Mini over USB (Speed is a low priority). However, I’ve come to learn that bot Firewire and USB are both limited to recognizing a maximum of 2TB. Is there any way around this? Where, exactly did you learn this? Firewire is a transport medium - AFAIK, it doesn’t care about drive sizes. And, BTW, USB sux - use Firewire. There may be OS volume size limitations. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [September 29, 2008, 7:32pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/3 "2008-09-29T19:32:48Z")
Correct me if I’m wrong, but won’t your RAID 5 enclosure look like a 1TB drive to the Mac? ---
**Author:** ![SunSandSuffering](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@SunSandSuffering](https://boards.straightdope.com/u/SunSandSuffering)\ **Post date:** [September 29, 2008, 7:48pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/4 "2008-09-29T19:48:56Z")
## Quote: Correct me if I’m wrong, but won’t your RAID 5 enclosure look like a 1TB drive to the Mac? Raid5 splits the data and creates additional parity information that is then striped to all available drives ([RAID - Wikipedia](http://en.wikipedia.org/wiki/RAID)). So with 5x 1TB drives the capacity of one is lost to parity giving a total usable capacity of 4TB. Link in the OP says: The MobileRAID MR5CT1 Series is an external compact RAID solution designed for file servers, video editing, and data storage. With up to 5TB of total storage capacity (64 bit OS, MAC OS 10.4 or above, Windows 64 bit Editions and LINUX 64 bit, supports over 2TB in one volume, **32 bit OS has max. 2TB per volume limitiation** ). So you’ll need a 64bit OS to use the full 4TB, operating system limitation rather than USB or Firewire limits. ---
**Author:** ![Nobody\_Special](https://avatars.discourse-cdn.com/v4/letter/n/bbce88/32.png) [@Nobody\_Special](https://boards.straightdope.com/u/Nobody_Special)\ **Post date:** [September 29, 2008, 7:49pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/5 "2008-09-29T19:49:54Z")
> [@UncleRojelio](#): > > Correct me if I’m wrong, but won’t your RAID 5 enclosure look like a 1TB drive to the Mac? Currently, it looks like a 2TB drive to my mac, but the admin panel shows it to be a 4TB drive. ---
**Author:** ![Nobody\_Special](https://avatars.discourse-cdn.com/v4/letter/n/bbce88/32.png) [@Nobody\_Special](https://boards.straightdope.com/u/Nobody_Special)\ **Post date:** [September 29, 2008, 7:53pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/6 "2008-09-29T19:53:12Z")
> [@](#): > > (64 bit OS, MAC OS 10.4 or above…) > > …So you’ll need a 64bit OS to use the full 4TB, operating system limitation rather than USB or Firewire limits. I’m running Mac OS X 10.5.5. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [September 29, 2008, 7:55pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/7 "2008-09-29T19:55:44Z")
> [@Nobody\_Special](#): > > Currently, it looks like a 2TB drive to my mac, but the admin panel shows it to be a 4TB drive. Per beowulff’s note it’s an OS issue for Mac 32 bit OSes, nothing to do with the drive or the IO medium, unless you change your OSes. Why is having 4 terabytes on one volume so critical? Simply config the raid as 2 volumes. ---
**Author:** ![SunSandSuffering](https://avatars.discourse-cdn.com/v4/letter/s/ee7513/32.png) [@SunSandSuffering](https://boards.straightdope.com/u/SunSandSuffering)\ **Post date:** [September 29, 2008, 7:58pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/8 "2008-09-29T19:58:31Z")
Apologies, I’m not really a Mac guy but I’m guessing that the OS is available in both 32bit and 64bit versions - and that you have the 32bit one. There is probably an equivalent of “Help/About” or “MyComputer/Properties” you get on Windows that will tell you. If it is 32bit can you make 2x 2TB drives - ie. use the array management to create one large Raid5 then partition it into 2 logical drives that the OS can see? ---
**Author:** ![Cleophus](https://avatars.discourse-cdn.com/v4/letter/c/a88e57/32.png) [@Cleophus](https://boards.straightdope.com/u/Cleophus)\ **Post date:** [September 29, 2008, 7:59pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/9 "2008-09-29T19:59:58Z")
Your Mac mini must have a Core 2 Duo processor, which is a 64-bit CPU. G4, Core Solo, and Core Duo-based Mac minis are 32 bit machines. ---
**Author:** ![Nobody\_Special](https://avatars.discourse-cdn.com/v4/letter/n/bbce88/32.png) [@Nobody\_Special](https://boards.straightdope.com/u/Nobody_Special)\ **Post date:** [September 29, 2008, 8:00pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/10 "2008-09-29T20:00:43Z")
> [@astro](#): > > Per beowulff’s note it’s an OS issue for Mac 32 bit OSes, nothing to do with the drive or the IO medium, unless you change your OSes. Why is having 4 terabytes on one volume so critical? Simply config the raid as 2 volumes. How would configuring the RAID as two 2TB volumes work? What would happen to the fifth drive? Could it still be configured as RAID 5? ---
**Author:** ![Nobody\_Special](https://avatars.discourse-cdn.com/v4/letter/n/bbce88/32.png) [@Nobody\_Special](https://boards.straightdope.com/u/Nobody_Special)\ **Post date:** [September 29, 2008, 8:03pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/11 "2008-09-29T20:03:11Z")
> [@Cleophus](#): > > Your Mac mini must have a Core 2 Duo processor, which is a 64-bit CPU. G4, Core Solo, and Core Duo-based Mac minis are 32 bit machines. Damn, it’s a Core Duo Mac. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [September 29, 2008, 8:03pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/12 "2008-09-29T20:03:24Z")
> [@SunSandSuffering](#): > > ## Quote: Correct me if I’m wrong, but won’t your RAID 5 enclosure look like a 1TB drive to the Mac? > > Raid5 splits the data and creates additional parity information that is then striped to all available drives ([RAID - Wikipedia](http://en.wikipedia.org/wiki/RAID)). So with 5x 1TB drives the capacity of one is lost to parity giving a total usable capacity of 4TB. Ah Thanks. I assumed that RAID5 included mirroring too. That’s what I get for not looking it up myself. ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 29, 2008, 8:05pm UTC](https://boards.straightdope.com/t/connecting-a-4tb-drive-via-usb-or-firewire-to-a-mac-mini/465751/13 "2008-09-29T20:05:29Z")
> [@SunSandSuffering](#): > > Apologies, I’m not really a Mac guy but I’m guessing that the OS is available in both 32bit and 64bit versions - and that you have the 32bit one. > > There is probably an equivalent of “Help/About” or “MyComputer/Properties” you get on Windows that will tell you. > > If it is 32bit can you make 2x 2TB drives - ie. use the array management to create one large Raid5 then partition it into 2 logical drives that the OS can see? Mac OS 10.5 includes both 32-bit and 64-bit support, and supports 64-bit programs and memory/drive access when running on 64-bit Intel processors (Core 2 Duo and later). The next version of Mac OS X will apparently have a 64-bit kernel as well.