Ubuntu 18.04: Slow boot problem when using LVM

If you install Ubuntu 18.04 with LVM, slow boot problem happens. This article will describe a way to avoid this problem. If you install Ubuntu 18.04 without LVM, this problem does not happen.

1 Slow boot problem when using LVM

systemd-analyze shows that kernel boot time takes a lot of time.

$ systemd-analyze
Startup finished in 34.003s (kernel) + 1.843s (userspace) = 35.847s
graphical.target reached after 1.822s in userspac

The wait-for-root in /usr/share/initramfs-tools/scripts/local times out after expiring 30 seconds (slumber value).

  case "$dev_id" in
    FSTYPE=$( wait-for-root "$dev_id" $slumber )
    wait_for_udev 10

The dev_id variable is assigned the value of RESUME which is defined at /etc/initramfs-tools/conf.d/resume. This UUID which is assigned to RESUME is the UUID of LVM swap partition.

$ cat /etc/initramfs-tools/conf.d/resume

2 Avoid slow boot problem when using LVM

Assign device file path of LVM swap partition to RESUME and use wait_for_udev instead of wait-for-root. This is the same with /etc/initramfs-tools/conf.d/resume in Debian 9.

$ sudo sed -e 's/^RESUME=/#RESUME=/g' \
     -i /etc/initramfs-tools/conf.d/resume
$ echo "RESUME=/dev/mapper/ubuntu--vg-swap_1" | \
  sudo tee -a /etc/initramfs-tools/conf.d/resume

Recreate initrd and reboot system.

$ sudo update-initramfs -u
$ sudo reboot

Kernel boot time is faster and you can use hibernation.

$ systemd-analyze
Startup finished in 1.920s (kernel) + 2.370s (userspace) = 4.291s
graphical.target reached after 2.196s in userspace