How to speed up boot time on lubuntu

1. Journal size limit

The time consuming systemd-journal-flush.service can be tweaked by a journal size limit.
Edit the Journal config file

sudo nano /etc/systemd/journald.conf

# uncomment and configure the value
SystemMaxUse=50M
# personnaly i use 2M ;)

# Then restart the journald service
sudo systemctl restart systemd-journald

1.1 Journal clean up

sudo journalctl --rotate
sudo journalctl --vacuum-time=1s

For information, the journal size is given by this command:

journalctl --disk-usage

2. Startup applications

Another step to speed up userspace load delay is to disable some startup applications
See how to show all of them : https://help.ubuntu.com/community/ShowHiddenStartupApplications

sudo sed -i "s/NoDisplay=true/NoDisplay=false/g" /etc/xdg/autostart/*.desktop 

See how to open the Startup Applications applet : https://help.ubuntu.com/stable/ubuntu-help/startup-applications.html

 gnome-session-properties

If you dont mind, disabling Backup Monitor and Updates Notifier will save boot time.

In addition to cmak.fr

I looked into What is the use of systemd-journal-flush.service?

sudo nano /etc/systemd/journald.conf

In the journal section uncomment and alter:

Storage=auto
SystemMaxFileSize=1G
SystemMaxFiles=5

Save & reboot.

keyboard-setup.service taking too long in startup (20+sec)

sudo gedit /lib/systemd/system/keyboard-setup.service

changed

TimeoutStartSec=10sec

Ubuntu 15.04 network manager causing slow boot

sudo nano /lib/systemd/system/NetworkManager-wait-online.service

edit from 30 to 15

[Service]
Type=oneshot
ExecStart=/usr/bin/nm-online -s -q --timeout=30

Long boot times on 18.04

sudo update-grub

Now

$ systemd-analyze critical-chain
graphical.target @59.292s
└─multi-user.target @59.291s
  └─kerneloops.service @59.278s +12ms
    └─network-online.target @59.277s
      └─NetworkManager-wait-online.service @52.596s +6.681s
        └─NetworkManager.service @45.820s +6.773s
          └─dbus.service @45.792s
            └─basic.target @45.790s
              └─sockets.target @45.790s
                └─snapd.socket @45.745s +44ms
                  └─sysinit.target @45.743s
                    └─swap.target @45.543s
                      └─dev-disk-by\x2duuid-f01c80a9\x2d4d4b\x2d4e60\x2dbeb0\x2d
                        └─dev-disk-by\x2duuid-f01c80a9\x2d4d4b\x2d4e60\x2dbeb0\x

and

$ systemd-analyze time
Startup finished in 4.770s (kernel) + 59.301s (userspace) = 1min 4.072s
graphical.target reached after 59.292s in userspace

From 7min 13.089s to 1min 4.072s a huge improvement, if anyone has any more improvements that I am not aware of please do share.

Here's my contribution to this little Show & Tell:

$ systemd-analyze critical-chain
The time after the unit is active or started is printed after the "@" character.
The time the unit takes to start is printed after the "+" character.

graphical.target @2.490s
└─multi-user.target @2.489s
  └─snapd.service @1min 34.450s +153ms
    └─basic.target @2.227s
      └─sockets.target @2.226s
        └─snapd.socket @2.205s +13ms
          └─sysinit.target @2.197s
            └─systemd-update-utmp.service @2.136s +54ms
              └─systemd-tmpfiles-setup.service @2.116s +9ms
                └─local-fs.target @2.108s
                  └─run-user-1000-gvfs.mount @1min 26.644s
                    └─run-user-1000.mount @1min 25.977s
                      └─local-fs-pre.target @192ms
                        └─systemd-remount-fs.service @172ms +10ms
                          └─systemd-fsck-root.service @110ms +39ms
                            └─systemd-fsckd.socket @109ms
                              └─-.slice @81ms

Compare this 2.49 seconds to SDC's answer of 59.29 seconds which has extra time consuming features I've removed from my boot-up:

  └─kerneloops.service @59.278s +12ms
    └─network-online.target @59.277s
      └─NetworkManager-wait-online.service @52.596s +6.681s
        └─NetworkManager.service @45.820s +6.773s
          └─dbus.service @45.792s
                └─snapd.socket @45.745s +44ms
                    └─swap.target @45.543s
                      └─dev-disk-by\x2duuid-f01c80a9\x2d4d4b\x2d4e60\x2dbeb0\x2d
                        └─dev-disk-by\x2duuid-f01c80a9\x2d4d4b\x2d4e60\x2dbeb0\x

Key features:

• Remove Network Manager Wait from startup.
• Remove snapd Refresh Service from startup.

Systemd Journal Control enhancements

$ cat /etc/systemd/journald.conf
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See journald.conf(5) for details.

[Journal]
#Storage=auto
# Aug 4 2018 - recommended: https://www.freedesktop.org/software/systemd/man/journald.conf.html
storage=persistent

The notable details are in bold.

Because journalctl files are not longer flushed at startup I have them setup to be vacuumed once a month:

• Systemd logs (`journalctl`) are too large and slow

Often I want to know what happened when the system crashed and I had to reboot. By default journalctl files don't show you the previous boots though. So I turned on multi-boot history:

• How do I find which Kernel Version I booted 2 weeks ago?

That's all for today. I'll try to remember to update this answer going forward.