Ubiquity crashes when partitioning the disk with ZFS installation

This is using a KVM console offered as HETZNER service.

The backend installation disk is a 8 TB SATA drive and the weird part of the logs is (to me):

. . .
Dec 18 15:24:28 ubuntu ubiquity: >>> Created a new GPT disklabel (GUID: 7AC8DCFB-DB54-8D48-9004-E1540F18BD4B).
Dec 18 15:24:28 ubuntu ubiquity: /dev/sda1: Created a new partition 2 of type 'VMware Virsto' and of size 50 MiB.
Dec 18 15:24:28 ubuntu ubiquity: Partition #2 contains a ext4 signature.
Dec 18 15:24:28 ubuntu ubiquity: /dev/sda3: Created a new partition 3 of type 'Sony boot partition' and of size 7.3 TiB.
Dec 18 15:24:28 ubuntu ubiquity: /dev/sda4: Created a new partition 5 of type 'VMware Virtual SAN' and of size 512 B.
Dec 18 15:24:28 ubuntu ubiquity: /dev/sda6:
Dec 18 15:24:28 ubuntu ubiquity: Failed to add #6 partition
Dec 18 15:24:28 ubuntu ubiquity: : Invalid argument
Dec 18 15:24:28 ubuntu ubiquity: Leaving.

The issue seems to affect only non-UEFI system configurations (after disabling CSM in the BIOS) I haven't been able to reproduce it, so I assume it has something to do with trying to install ZFS (GPT??) on disks >4TB, but I haven't been able to test that hypothesis.

Right it's an issue with CSM but I haven't been able to figure out exactly what and produce a test case. The 4TB limit is a very good point though. I'll do some more testing based on this hypothesis after EOY break.
Thanks for testing and your help.

The issue stems from the assumption made by the installer that only EFI systems need to label disks as GPT. I've created a non-UEFI VM with an 8 GB thin-disk and was able to reproduce the issue, but the following diff was enough to make the installation to succeed:

---

root@ubuntu:/usr/share/ubiquity# diff -u zsys-setup.orig zsys-setup
--- zsys-setup.orig 2019-12-31 20:53:20.861713613 +0200
+++ zsys-setup 2019-12-31 21:23:50.115938723 +0200
@@ -167,9 +167,11 @@
  sfdiskopts=""
  partprefix="${disk}${PARTBASE}"

+ labeltype=$(sfdisk -l "${disk}"|grep '^Disklabel type:'|awk '{print $NF}')
+
  echo "I: Formatting disk $disk with partitions grub:${partgrub} ext:${partext} bpool:${partbpool} rpool:${partrpool}"

- if [ "${IS_EFI}" = "true" ]; then
+ if [ "${IS_EFI}" = "true" -o "${labeltype}" = "gpt" ]; then

   # Improvement: Delete all the partitions but the ESP
   # We should be only 1 or 2 partittion but well it can be made generic

---

It is a bit rough and doesn't apply to current HEAD (I applied it to the live image code) but it shows the issue and how it can be patched/"workarounded".

Regards, and happy new year.

Thank you for the patch. I'll apply it.

Looking at partman-auto it uses gpt instead of msdos disklabel if the disk is larger than 2TB. It was the case of the original bug report and the duplicate.

I attached a branch that fixes this issue. It's a slightly different implementation from what you suggested but basically the idea is the same.

I tested it on a system with gpt and msdos disk labels with and without an efi firmware.

Thanks for your fix (it's indeed much cleaner than mine) and I look forward to test it.

Do you plean to integrate it in any 19.10.x installer release? Is there any daily build I can test with the fix included?

We'll do a release of ubiquity with this fix likely this week or next. It'll close this bug report automatically and you'll be notified. Then, next daily of focal will have the fix.

It won't be released to 19.10. There is no point release or daily images for non-LTS releases.

Setting back to "In progress", there is still one bit of the fix missing according to 1856863 to make a gpt partition bootable on legacy bios.

I meant bug 1858966

This bug was fixed in the package ubiquity - 20.04.5

---------------
ubiquity (20.04.5) focal; urgency=medium

  [ Jean-Baptiste Lallement ]
  * zsys-setup: Drives bigger than 2TB use GPT but if the machine has been
    booted in legacy mode the ESP is not created. Rely on the label type
    instead of the firmware to know how to partition the disk (LP: #1856863).
    Thanks to Pablo Mendez Hernandez for the investigation.

  [ Iain Lane ]
  * Automatic update of included source packages: choose-mirror
    2.78ubuntu7, console-setup 1.194ubuntu2, partman-basicmethods 70,
    partman-jfs 58, partman-lvm 132, preseed 1.71ubuntu11, shim-signed
    1.41.

  [ Dimitri John Ledkov ]
  * Automatic update of included source packages: partman-auto
    134ubuntu13.

 -- Dimitri John Ledkov <email address hidden> Wed, 19 Feb 2020 20:15:17 +0000