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I realize that there can be an issue using 3TB drives with Ubuntu:

Trouble creating 3TB ext4 partition due to msdos-partition-table-imposed error

I read the answer given here but am still unsure, plus the answer is a few years old now.

The partition of free space I am trying to install to is 1.8T, so will this still cause the same problem as it's under the 2TB limit where problems start (see James Henstridge's answer above)?

I am trying to create a dual boot machine, where windows 10 is already installed, I got as far as creating the root partition as shown here:

https://itsfoss.com/install-ubuntu-1404-dual-boot-mode-windows-8-81-uefi/

However, when I try to add the swap partition I get the error above.

If this is the same problem, I'd like to be hand held through the whole process of repartitioning the dice as I really don't understand the answer above properly.

Bazman
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1 Answers1

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With MSDOS/MBR partition tables, partitions are defined mainly by two numbers, size and offset.

Both are 32 bit unsigned integers, so the maximum value they can hold is 232. The unit used by these numbers is a sector, which normally has a size of 512 bytes. This means, both the maximum size of a partition as well as the maximum offset/starting address must be lower than 232×512 bytes, which equals 2TB.

So, if you have 3TB in total, and the first 1.8GB are occupied by Windows, you can still create another partition with the offset of 1.8TB very well, as you say you did with your Ubuntu root partition. The remaining space is smaller than 2TB anyway, so size will not be a constraint. However, if we say we want the root partition to take all remaining space except for e.g. 8GB for swap, the offset of that swap partition will be far outside the 2TB range, and thus not supported.

You have a few options now:

  • Create the swap partition before the Ubuntu root partition, like this:

       0GB - 1800GB  Windows (or whatever)
1800GB - 1808GB  Ubuntu Swap
1808GB - 3072GB  Ubuntu /

    That way all starting offsets will be below the 2TB limit.

  • Don't create a swap partition at all and use a swapfile instead. The process is described e.g. in How do I add a swap partition after system installation?

  • Use GPT instead of the old MSDOS/MBR partition table. This would require converting your existing disk with Windows though. The process is probably not trivial and always comes with a risk of something going wrong and causing you to lose all data...

Byte Commander
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