For some time, my boot process is taking too long (almost 1 min.).

systemd-analyze time

shows that kernel is taking 35.765s

Looking at dmesg , it seems that the problem is with mounting file systems:

... [ 2.186084] sdb: sdb1 sdb9 [ 2.186919] sd 2:0:0:0: [sdb] supports TCG Opal [ 2.186922] sd 2:0:0:0: [sdb] Attached SCSI disk [ 2.499795] ata5: SATA link down (SStatus 0 SControl 300) [ 2.844320] clocksource: Switched to clocksource tsc [ 35.670493] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: (null) [ 35.782128] ip_tables: (C) 2000-2006 Netfilter Core Team [ 35.803610] systemd[1]: systemd 237 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 default-hierarchy=hybrid) ...

My /etc/fstab looks like this:

# <file system> <mount point> <type> <options> <dump> <pass> /dev/mapper/ubuntu--vg-root / ext4 errors=remount-ro 0 1 # /boot/efi was on /dev/sda1 during installation UUID=3996-2381 /boot/efi vfat umask=0077 0 1 #/dev/mapper/ubuntu--vg-swap_1 none swap sw 0 0 /dev/mapper/cryptswap1 none swap sw 0 0

How can I troubleshoot this ?

EDIT: looking closely at the boot messages (after removing the quiet option in grub), I spotted this suspicious line:

gave up waiting for suspend/resume device

I think my swap is encrypted, and I also think the UUID in /etc/initramfs/conf.d/resume does not correspond to any device.

Should I disable resume/suspend? and how to do that?