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I just bought an external USB disk called "Freecom Hard Drive XS 3TB" (user manual).

Immediately after unpacking, I plugged it into Ubuntu and it shows as two devices (/dev/sda is my laptop's drive):

GParted 3 devices

The external drive is both /dev/sdc (2 TiB) and /dev/sdd (746GiB).

What I tried:

  • I removed all partitions they contained, but that obviously does not make them a single /dev device.
  • I created a new GPT disklabel, for each device, then restarted it. Did not work either.
  • Exact same problem on a Mac made in 2013 running Mavericks.

Here is what gdisk has to say:

# gdisk -l /dev/sdc
GPT fdisk (gdisk) version 0.8.10

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sdc: 4294967295 sectors, 2.0 TiB
Logical sector size: 512 bytes
Disk identifier (GUID): D3C6A90D-FA52-42C0-9683-F0F599BFD5B1
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 4294967261
Partitions will be aligned on 2048-sector boundaries
Total free space is 4294967228 sectors (2.0 TiB)

Number  Start (sector)    End (sector)  Size       Code  Name
# gdisk -l /dev/sdd
GPT fdisk (gdisk) version 0.8.10

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/sdd: 1565565872 sectors, 746.5 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): B8356612-A14C-4830-8CD8-871A26090A09
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1565565838
Partitions will be aligned on 2048-sector boundaries
Total free space is 1565565805 sectors (746.5 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name
#

QUESTION: How to make my external disk appear as one single device?

I run Ubuntu 2015.04 on Lenovo Thinkpad T520.

An Amazon review gives me hope that it is not a hard-coded limitation:

It did take some tinkering to format it as a single 3TB drive but as long as the majority require compatibility with Windows XP I don't blame Freecom. supportuk@freecom.com sent a speedy response to my request attaching a program to set the drive to a single 3TB partition. Sadly it is a windows program.

Maybe related:

Community
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Nicolas Raoul
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  • That drive should have had a note on the top of the box or something like similar to "to make it backward compatible, it is formatted to appear as two seperate drives in Windows explorer, and that as this is hard coded into the devices firmware you cannot undo this by reformatting the drive". – Terrance Nov 25 '15 at 07:03
  • @Terrance: I have the whole package here, it has no such note. The user manuel (linked at the beginning of the question) does not mention anything similar either. – Nicolas Raoul Nov 25 '15 at 07:27
  • That is actually in the reviews of that drive here where 2 of the four talked about it. The manuals cover all the XS products, but no sizes particularly. You might want to contact Freecom direct. Those XS products are showing that they are discontinued. – Terrance Nov 25 '15 at 07:29
  • @NicolasRaoul the most logical explanation is as, Terrance said that is is built into the firmware of the USB controller in the drive. Contacting Freecom, or the vendor that sold you the drive is probably your best bet for an explanation. – Tobias Nov 25 '15 at 07:31
  • The vendor is Amazon, from which I probably won't get much support :-) – Nicolas Raoul Nov 25 '15 at 07:40
  • @Terrance: Nice find! Question updated. – Nicolas Raoul Nov 25 '15 at 07:45
  • @NicolasRaoul I missed that review of the drive, but maybe they have that application somewhere where you can get your hands on it to reformat your drive as 1 drive. I wish you the best! =) – Terrance Nov 25 '15 at 07:53
  • Maybe you can use LVM to setup a single logical disk spanning both drives. – muru Nov 26 '15 at 06:12

3 Answers3

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I ended up sending an email to Freecom, and they sent me a Windows executable called Freecom Mode Change Tool.exe. I asked for a Linux version but they told me:

Malheureusement non, le seul outil disponible fonctionne sur Windows uniquement.
[Unfortunately no, the only available tool works on Windows only.]

I had a hard time finding a Windows machine but when I did I executed the tool and was able to change it from "Split Mode" to "Standard Mode":

Freecom Hard Drive Mode Change

The disk now shows correctly as a single 3TB device:

Freecom Hard Drive XS 3TB device

Any Ubuntu-only solution would be very welcome!

Nicolas Raoul
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The reason your disk showed up as a 2TB disk and a second, smaller, disk is that a lot of the (older) OSs out in the wild do not supports disks and partitions bigger than 2TB.

By "formatting" the device like this in the firmware, it appears to be two physical disks. By doing this, the manufacturer ensures that everyone can use the full size of the disk.

This Seagate article gives a bit more information about these "virtual" disks. Seagate also provides a Windows tool called DiskWizard to format the HDD as one big disk.

Instead of reformatting your disk, you can also use both disks as LVM partitions. They can then be used as one big disk. Create partitions smaller than 2 TB, and add them to a Logical Volume Manager (LVM) volume group, then create a logical LVM volume greater than 2 TB. Once the logical volume is created, you can format it with a file system of your choice.

This IBM article shows you one way of creating partitions bigger than 2TB on Ubuntu. Your kernel needs GPT support for that.

NZD
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  • "By formatting the disk like this": Would you mind replacing "formatting" with a less ambiguous verb? Unless you really meant https://en.wikipedia.org/wiki/Disk_formatting Thanks :-) – Nicolas Raoul Nov 25 '15 at 07:07
  • "Your kernel needs GPT support for that": I use the default kernel of 2015.04, which supports GPT. – Nicolas Raoul Nov 25 '15 at 07:08
  • It shows up as two devices, not two partitions. I think your answer is very misleading. – Tobias Nov 25 '15 at 07:32
  • @Tobias: I don't think yr criticism is deserved by NZD. She/he/it probably knows quite well the difference between primary, extended, logical partitions and "devices". In any case Nicolas Raoul's HDD *was* partitioned, although that "partitioning" apparently took place at hardware level and not at HFS level, resulting in 2 devices. Clearly the 2 (i.e. partition and device) are somewhat different beasts when dealing with them, but when you come to think of them, the difference in their nature is that 2 firmware-defined devices on 1 HDD just mimic a physical "partition". +1 to NZD. – Cbhihe Nov 25 '15 at 18:58
  • @Tobias: ... and for that matter, just by being consistent in yr logik, you could also criticize Barafu Albino's answer above, on the exact same grounds as you did NZD. – Cbhihe Nov 25 '15 at 19:01
  • @Cbhihe Barafu Albino's answer is much more accurate than NZDs. It proposes an actual solution to the problem, and it isn't based on false premises, such as NZD's answer (two partitions, instead of two devices). I can't imagine how NZD's answer would help the person asking the question, or anyone experiencing the same issue. – Tobias Nov 26 '15 at 10:47
  • @Tobias: I am not disputing that fact or the merit of one answer other the other. I just think that you went fast in crucifying one answer, while you look the other way as the second one similarly abused the term "partition". I don't want to make a war of religion out of this, and rest assured I am also not advocating in favor of mediocrity on AU. I still think you were a bit swift with yr criticism. Anyway, this is not the place to discuss that. Take it to a chat if you wish although I don't see the point. – Cbhihe Nov 26 '15 at 14:25
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This is hardware. You can not turn it off (The review you cited suggests you can reflash firmware).
If you want to use it as a single disk, there are several ways in linux to combine several partitions into one. I recommend to set up BTRFS RAID 0. Instructions here. It will not incur noticable performance overhead. With BTRFS you can also turn on compression, which increases the read/write speed for external HDDs.

Barafu Albino
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