[Lugstuff] 4TB external drive

Thomas Gallen kaori.hinata at gmail.com
Fri May 21 10:10:19 EDT 2010

> Dear Linux user group,
> I recently got a Western Digital 4TB Book external drive and have a
> problem formatting it.  Plugging into a Mac it shows 4 trillion available
> bytes and by a click with the mouse it formats the 3.6 TB (2 internal drives)
> as a single partition.  That, of course is not readable by Linux.

Actually, it might depend on the distribution but Linux does support HFS+ partitions quite well (don't know about the journaling support though). This is, however, beside the point though.

> Running RHEL, after plugging into the USB port the  dmesg  shows a
> "very big device" but can't determine properly its size.  I was told
> to put a GPT system on.  fdisk is not supposed to work while parted
> should.  With parted I can make a GPT lable, but my computer "sees"
> only about 2 TB max, I can't even create a 3TB partition.

Hmm, a 2TB max makes it seem like there's A.) still an MBR partition table on there (as it appears you've been told by others) or B.) the kernel was compiled without the "Support for large (2TB+) block devices and files" option.

For A, if you have access to Palimpsest (the GUI partitioning tool) then it should be able to tell you (just under the volume name) if it is indeed properly formatted with a GPT partition table. If you want to be sure, you can always select the volume and erase it again with a GPT partition table. As far as command line tools, you already know about parted. If you prefer the fdisk command interface then I'd suggest gdisk (it's what I use an it's quite effective).

For B, you can find the option for "Support for large (2TB+) block devices and files" under "Enable the block layer" in menuconfig. If you have a .config (kernel config) sitting around or have access to /proc/config.gz then you can search through either for the option "LBDAF" to see if it was enabled. Considering you said this was RHEL though, I don't see would not be enabled (or included) so I think this is the less likely of the possibilities. 

As I don't own that particular device or have access to one I'm afraid I can't offer any additional advice. Sorry.

Hope this helps,
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