R4.0 fails to start VMs (mount root from xvda) due to 4kB sectors?

[Ilpo Järvinen]

Hi,

I installed R4.0 into a machine with sda (for /boot only) & NVMe drives
(I had to use manual partitioning for this but I followed the
custom installation instructions on qubes-os.org except I used a larger
metadata size). It turns out that Qubes fails to start any VM successfully
because it fails to correctly detect partitions on /dev/xvda and therefore
has no root to mount (and bails out).

I've tried to track down the cause and it looks as if the problem is
caused by the 4kB/4kB sector size of the NVMe drive which causes
misinterpretation of the partition table(?). If I use fdisk on the
/dev/qubes_dom0/vm-debian-9-root directly, I don't see the correct
partitions (and that is then -snap'ed into the vm's xvda) but if I 'dd'
it into a local file, the three partitions show up correctly so the data
itself on LV seems ok.

Is this expected behavior with R4.0 (I think R3.2 worked just fine with
a similar 4kB/4kB SSD drive)? Does somebody know a way to workaround this
problem (other than changing the SSD's logical sector size to 512B which,
I guess, might have some performance implications).

The R4.0 I used is self-build but I've installed a working system from the
very same copy successfully on other machines so I doubt some misbuild
alone can explain the problem (but those working systems did not have a
4kB/4kB drive).


--
i.