I'm trying to create a logical partition inside an extended partition but gparted doesn't let me do it.

My setup:

  • System: Ubuntu 16.04
  • Partitioning software: gparted 0.25.0


  • /dev/sda1: extended partition (covers all the space)
    • /dev/sda6: 32GiB system root partition
    • /dev/sda7: 113GiB data partition
    • /dev/sda5: 664GiB main data partition
    • 114GiB Free space I want to use as new partition, not as a part of sda5
    • /dev/sda8: 8GiB swap

Do I have to umount the system root partition?

Is there a workaround?

Is it just a bug?

Why does this happen?

I don't want to run a live CD/USB just to create a partition.

Yes, I know partition numbers are not ordered, but I'm using UUID anyway so who cares. I also know there are almost 70GB missing. This is because GiB is not equal to GB, and the brands sell HDD with measuring unit of 10^12 bytes instead of 2^40 bytes.

  • How exactly gparted doesn't let you? Have you tried other tools (like fdisk, gdisk)? – Kamil Maciorowski Mar 31 '17 at 14:24
  • 2
    Please leave this question open (don't accept your own answer), so maybe someone will eventually explain to us what happened. I find it interesting. I have changed the question title and emphasized the "why?" part. – Kamil Maciorowski Apr 1 '17 at 22:23
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    maybe the correct question should be something like: why do logical partitions need a 1MB gap at each side in gparted? – Falk Apr 2 '17 at 14:07
  • this might have nothing to do with not using live session. from a live usb i had the same problem and solved in the same way. – user162573 Apr 19 '18 at 16:20
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    When do logical partitions happen to need 1MB gap at each side in gparted? on unix.stackexchange – user162573 Apr 19 '18 at 16:32

I solved it. All I've done is letting 1MB gap at each side of the partition and setting align to 'none'.

Still I don't understand why this is necessary.

| improve this answer | |
  • 1
    +1 Although this short answer gives a workaround only and explains nothing, I appreciate it could be a life-saver for someone with similar problem. – Kamil Maciorowski Apr 1 '17 at 22:23
  • How have you found about this trick? --- As it is the answer was short but efficient for me too (after solus linux failing to format and install on that partition; worked after formatting it in gparted as you said). - Only I wasn't able to format from a live usb, until I used those settings. This might have nothing to do with being in live session or not. – user162573 Apr 19 '18 at 16:16
  • @cipricus I had an intuition and tried it out. – Falk Apr 19 '18 at 16:23
  • Sometimes trying out is easier than read lot's of documentation and sourcecode. On the other hand just tring things can be dangerous. – Falk Apr 19 '18 at 16:27
  • the possible question that you phrased in a past comment : - unix.stackexchange.com/q/438773/32012 – user162573 Apr 19 '18 at 16:33

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