Diagnose and fix slow boot on ubuntu.

Method 1 :

very slow boot on Ubuntu to update GRUB so it passes this option to the kernel automatically on boot:

Edit the file

/etc/default/grub

so that string noresume is included in the

GRUB_CMDLINE_LINUX_DEFAULT

line, for example:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash noresume"

Run this command to update GRUB:

sudo update-grub

Reboot machine

Method 2 :

Try from “No splash screen to Kernel” to find which processes are taking the most time for booting.

A start job is running for Raise network interfaces (1min 20s / 6min 20s)

So, we need to reduce time for this process to save boot time. To do so,

You have to edit,

sudo nano /etc/systemd/system/network-online.target.wants/networking.service

Find,

TimeoutStartSec=5min

Change to,

TimeoutStartSec=5s

and

reboot

Method 3 :

You can configure the timeout for Start Job and Stop Jobs.

Edit /etc/systemd/system.conf with elevated privileges and change/add two lines that are commented by default from 90 seconds to 5 (or whatever you prefer) and uncomment it:
from:

#DefaultTimeoutStartSec=90s
#DefaultTimeoutStopSec=90s

to:

DefaultTimeoutStartSec=5s
DefaultTimeoutStopSec=5s

After that, apply the changes by update your initramfs with the command:

sudo update-initramfs -u

Method 4 :

Diagnose and fix very slow boot on Ubuntu Using fsck Disk Check

Remove

fsck.mode=skip

from

/etc/default/grub

,and do

sudo update-grub

check your file system first    1. Live boot your Ubuntu machine
    2. open a terminal
    3. sudo fdisk -l

    4. identify the /dev/sdXX device name for your “Linux Filesystem”
    5. type ,

    sudo fsck -f /dev/sdXX

        replacing sdXX with the number you found earlier
    6. repeat the fsck command if there were errors
    7. reboot