LVM autoextend not working in 4.2

I’ve read topics such as LVM Autoextend Help and Bricked: cannot run any qube => free space in thin pool reached threshold and other materials on the autoextend configuration, but could not find what’s wrong in my setup.

I’ve just installed 4.2-rc2 (which is great, btw) and am trying to restore the VM backups from an external hard drive. During the restore process, while the VM is being extracted, the vm-pool gets full and the restore process is stoped. I’d expect the pool to expand when the usage of the pool increased above the autoextend threshold. Is this the expected behavior, or the autoextend would only run in other situations?

The /etc/lvm/lvm.conf settings are the default ones:

snapshot_autoextend_threshold = 100
snapshot_autoextend_percent = 20
thin_pool_autoextend_threshold = 90
thin_pool_autoextend_percent = 20

I’ve also tried changing thin_pool_autoextend_threshold = 80 and thin_pool_autoextend_percent = 30 and this does not work even after rebooting.

I’m using a 512 GB NVMe disk which was partitioned by the qubes installer using the simpler customized setup (there is an option there to create the default partitioning scheme). I just changed the initial setup to increase the size for the swap and the / mount point. So, at the end of the installation, the vm-pool was created and I ended up with the following:

  • /dev/sdb1, 600 MB, /boot/efi
  • /dev/sdb2, 1 GB
  • /dev/sdb3, 99,12 GB, LUKS partition
    • root-pool: 30 GB
    • vm-pool: 17 GB
  • Free space: 376,2 GB

Now, I’m using 15 GB of the vm-pool. When I try to restore one of the VMs from the backup file which is around 18 GB, I can see the data usage in the disk monitor widget increase until it reaches 100% and get the notifications that there is no space in the pool.

So, I’m wondering what to do now, and also posting to confirm if the r4.2 installer setup is correct. For instance:

  • Is it right that the volume group qubes_dom0 is just the size of the swap and both thin pools? Should the free space be alocated inside the volume group for autoextend to work correctly? I could not find where to configure this in the installer option I used (not the blivet-gui).
  • Would autoextend work in the restore operation described above, or for this use case I should extend the vm-pool size manually to increase available space before restoring the VMs?
  • I could not find the name of the device mapper daemon (the dmeventd described in lvm.conf) to check if it is running. How should I check this?