I'm building the system in VirtualBox with a CentOS 7.5.1804 guest on a Windows 10 host using the v8.2 systemd book (the current is v8.3, but the partitioning content is the same), and I got a little stuck on the partitioning instructions (page 16). I initially created a virtual hard disk of around 100 GB, and during installation of the guest, I created a partition of 40 GiB for my LFS build site (/dev/sda3).

The partitioning instructions don't really say enough. It says to create a partition from empty space or use an empty partition, that's fine I already made a partition. It goes on to discuss convenience partitions, which I understand. I made /home and /var partitions on my laptop, so that makes sense. I got stuck on creating these convenience partitions within /dev/sda3, as it I found it to be implied that they were supposed to be within the LFS partition. cfdisk would show these partitions within a partition as sda3p1, etc. however on writing the partition table, it says the re-read went poorly and to try using partprobe which I did. partprobe says:

Error: Partition(s) 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64 on /dev/sda3 have been written, but we have been unable to inform the kernel of the change, probably because it/they are in use. As a result, the old partition(s) will remain in use. You should reboot now before making further changes.

The device was in fact mounted, so I rebooted the VM and this was still an issue. I then deleted the partition table from the device and tried everything again without it being mounted, and I got the same result.


  1. Is it possible to partition a partition? Logically, I think it would be as a hard disk is nothing but a big partition, and we partition hard disks.
  2. If it is possible to partition a partition, what is the correct way to do it in Linux?
  • You don't partition sda3; you partition sda. Dec 22, 2018 at 19:49

1 Answer 1


No, you don't partition a partition.

And you can only have 4 primary partitions, one of which can be an extended partition that can contain logical partitions.

Personally, I'd leave it alone. When I did my LFS system (18 years ago) I kept it all on one partition. Easy to clone data, etc. off to a new one if really needed, but I'd keep it simple as you can for your first trip down the LFS lane ...

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