Ubuntu 16.04: Avoid boot delay around activating LVM swap

When install Ubuntu 16.04 with LVM, there is a boot delay problem with mounting LVM swap partitions.

This article will solve boot delay problem.

 

1 Boot delay problem with mounting LVM partions

Checking printk time with dmesg, a message "EXT4-fs (dm-0): mounted filesystem with ordered data mode" has 5 seconds delay.

[    1.126338] FDC 0 is a S82078B
[    1.830136] tsc: Refined TSC clocksource calibration: 3392.321 MHz
[    1.830140] clocksource: tsc: mask: 0xffffffffffffffff max_cycles:
0x30e5f904771, max_idle_ns: 440795373543 ns
[    6.984151] EXT4-fs (dm-0): mounted filesystem with ordered data mode.
Opts: (null)
[   10.421370] systemd[1]: systemd 229 running in system mode.
(+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP
+LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID
+ELFUTILS +KMOD -IDN)
[   10.421397] systemd[1]: Detected virtualization kvm.

This is because Ubuntu 16.04 installer does not support LVM swap.

2 Solution

Change RESUME value from UUID to /dev/mapper/* in /etc/initramfs-tools/conf.d/resume and update initrd.

$ sudo su -c 'echo RESUME=/dev/mapper/ubuntu--vg-swap_1 \
> /etc/initramfs-tools/conf.d/resume'
$ sudo update-initramfs -u
$ sudo reboot

"EXT4-fs (dm-0): mounted filesystem with ordered data mode" has no delay.

[    1.095876] FDC 0 is a S82078B
[    1.507060] EXT4-fs (dm-0): mounted filesystem with ordered data mode.
Opts: (null)
[    1.807522] tsc: Refined TSC clocksource calibration: 3392.321 MHz
[    1.807526] clocksource: tsc: mask: 0xffffffffffffffff max_cycles:
 0x30e5f904771, max_idle_ns: 440795373543 ns
[    2.648513] systemd[1]: systemd 229 running in system mode.
(+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP
+LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID
+ELFUTILS +KMOD -IDN)
[    2.648542] systemd[1]: Detected virtualization kvm.