我在 Virtualbox VM 中运行 Xubuntu 20.04。VM 映像存储在健康的 SSD 上。安装后它启动速度很快。我不记得/没有注意到启动过程何时变慢，所以我必须找到另一种方法。
systemd-analyze blame/critical chain/plot 输出对我来说毫无意义。因此，我已经禁用了一半的服务，但没有成功。
输出如下：
systemd-analyze critical-chain
The time when unit became active or started is printed after the "@" character.
The time the unit took to start is printed after the "+" character.
graphical.target @1min 34.321s
└─multi-user.target @1min 34.319s
└─snapd.seeded.service @1min 34.144s +174ms
└─snapd.service @1min 29.467s +4.669s
└─basic.target @1min 29.255s
└─sockets.target @1min 29.252s
└─snapd.socket @1min 29.225s +19ms
└─sysinit.target @1min 29.101s
└─systemd-timesyncd.service @1min 28.556s +539ms
└─systemd-tmpfiles-setup.service @1min 28.441s +89ms
└─local-fs.target @1min 28.402s
└─run-user-1000.mount @1min 33.447s
└─local-fs-pre.target @1.220s
└─keyboard-setup.service @715ms +503ms
└─systemd-journald.socket @677ms
└─-.mount @625ms
└─system.slice @625ms
└─-.slice @625ms
$ systemd-analyze blame
1min 27.486s dev-sda5.device
4.669s snapd.service
1.611s networkd-dispatcher.service
1.445s udisks2.service
1.365s accounts-daemon.service
1.282s dev-loop0.device
1.278s dev-loop1.device
1.218s dev-loop2.device
1.184s dev-loop3.device
1.168s dev-loop4.device
1.162s dev-loop5.device
1.152s dev-loop6.device
1.022s lightdm.service
985ms systemd-logind.service
743ms apache2.service
731ms NetworkManager.service
709ms ModemManager.service
692ms systemd-resolved.service
675ms avahi-daemon.service
637ms upower.service
632ms polkit.service
539ms systemd-timesyncd.service
536ms thermald.service
519ms [email protected]
503ms keyboard-setup.service
474ms wpa_supplicant.service
471ms gpu-manager.service
460ms systemd-journald.service
401ms ssh.service
396ms apport.service
356ms grub-common.service
355ms e2scrub_reap.service
349ms teamviewerd.service
345ms systemd-udevd.service
344ms phpsessionclean.service
335ms alsa-restore.service
322ms apparmor.service
276ms lvm2-lvmpolld.service
270ms systemd-udev-trigger.service
269ms colord.service
268ms systemd-journal-flush.service
253ms ubuntu-fan.service
247ms vboxadd-service.service
210ms kerneloops.service
190ms systemd-tmpfiles-clean.service
188ms hddtemp.service
174ms snapd.seeded.service
152ms snap-snapd-11107.mount
152ms lm-sensors.service
