[parted-devel] 3TB drives available at retail; anyone tried parted with 'em?

[Jim Meyering]

Phillip Susi wrote:

> On 9/22/2010 9:17 PM, John Gilmore wrote:
>> I received a 3TB Seagate drive today.  Due to PC-clone boot issues,
>> they don't sell it as an ordinary SATA drive, but you can buy the external
>> USB drive and merely take it out of the box.  It's $200.  See:
>>
>>   http://www.newegg.com/Product/Product.aspx?Item=N82E16822148580
>>
>> I'm writing to suggest that parted developers consider getting
>> such a drive and testing with it.  It's the first ordinary SATA
>> drive holding more than 2TB.

An important point John mentioned privately:

  > When removed from its USB housing, it's an ordinary 512-byte sectored disk.

>> Here's a review of the drive (both as a SATA drive and in its native
>> USB2 and optional USB3 interfaces):
>>
>>   http://www.anandtech.com/show/3858/the-worlds-first-3tb-hdd-seagate-goflex-desk-3tb-review/
>
> Interesting read, but there are a few errors in the article, which you
> seem to have already hinted at.  The bios can boot a gpt disk just fine.
>  The problem is with the boot loader.  The Windows boot loader expects
> to find an active partition to chain load, which it won't with a stock
> gpt disk.  As you found, you can however, use a hybrid where you expose
> the Windows boot partition via the MBR to trick the windows boot loader
> into working.  Now that I look at it though, it looks like the Windows
> boot loader will fail if the partition starts beyond the 2tb mark, so

Right.  "at or beyond the 2TiB mark".

The MBR format allocates 32 bits for each partition starting sector
number, and at 512-bytes/sector, each partition must start before the
2TiB mark (i.e., before byte 2^32 * 512).  Similarly for length.
The maximum MBR partition length is 2TiB-1 bytes.

Other good reasons to use GPT whenever possible:
  - partitions can have names
  - all partitions are equal (mostly): no hassle with primary,extended,logical
      since with GPT, they're all "primary"
  - far superior protection against partition corruption

> you might need a dedicated boot partition below that.  Grub2 does not
> have that limitation, and will boot just fine from a gpt disk.