为什么 Ubuntu budgie 18.10 在我的带有 HDD 的上网本 ASUS X201EP 上启动需要这么长时间。没有双启动，上网本只安装了 Ubuntu。Ubuntu 从 18.04 升级，没有全新安装。启动时间比 Ubuntu 18.04 长。
$ systemd-analyze
Startup finished in 3.327s (firmware) + 4.594s (loader) + 4.539s (kernel) +
1min 18.844s (userspace) = 1min 31.306s
graphical.target reached after 1min 14.162s in userspace
$ systemd-analyze blame | head -20
23.886s nmbd.service
18.962s dev-sda2.device
15.733s systemd-journal-flush.service
13.936s udisks2.service
12.884s networkd-dispatcher.service
10.675s snapd.service
10.005s ModemManager.service
9.179s dev-loop7.device
9.168s plymouth-quit-wait.service
9.153s lightdm.service
9.086s NetworkManager-wait-online.service
9.030s ufw.service
8.736s accounts-daemon.service
8.647s dev-loop4.device
8.535s dev-loop3.device
8.434s dev-loop6.device
8.290s dev-loop5.device
7.993s NetworkManager.service
7.964s dev-loop0.device
7.544s dev-loop1.device
$ 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 @1min 14.162s
└─multi-user.target @1min 14.160s
└─smbd.service @1min 10.516s +3.643s
└─nmbd.service @46.627s +23.886s
└─network-online.target @46.625s
└─NetworkManager-wait-online.service @37.538s +9.086s
└─NetworkManager.service @29.536s +7.993s
└─dbus.service @29.523s
└─basic.target @28.866s
└─sockets.target @28.866s
└─snapd.socket @28.846s +19ms
└─sysinit.target @28.740s
└─apparmor.service @24.626s +4.113s
└─local-fs.target @24.611s
└─run-user-1000.mount @1min 7.287s
└─local-fs-pre.target @7.454s
└─systemd-tmpfiles-setup-dev.service @6.190s +1.26
└─systemd-sysusers.service @4.776s +1.411s
└─systemd-remount-fs.service @4.522s +250ms
└─systemd-journald.socket @4.423s
$ journalctl -b --unit smbd
-- Logs begin at Sat 2018-07-07 19:57:48 CEST, end at Wed 2018-10-24 21:45:47 CE
oct. 24 20:31:38 fred-X201EP systemd[1]: Starting Samba SMB Daemon...
oct. 24 20:31:42 fred-X201EP systemd[1]: Started Samba SMB Daemon.
$ journalctl -b --unit nmbd
-- Logs begin at Sat 2018-07-07 19:57:48 CEST, end at Wed 2018-10-24 21:51:09 CE
oct. 24 20:31:15 fred-X201EP systemd[1]: Starting Samba NMB Daemon...
oct. 24 20:31:38 fred-X201EP systemd[1]: Started Samba NMB Daemon.
后
sudo systemctl stop smbd
sudo systemctl disable smbd
sudo systemctl disable NetworkManager-wait-online.service
和
$ systemd-analyze critical-chain
graphical.target @1min 13.716s
└─multi-user.target @1min 13.716s
└─nmbd.service @36.178s +37.536s
└─network-online.target @36.176s
└─network.target @36.174s
└─NetworkManager.service @28.766s +7.405s
└─dbus.service @28.714s
└─basic.target @28.706s
└─sockets.target @28.706s
└─snapd.socket @28.680s +26ms
└─sysinit.target @28.630s
└─apparmor.service @24.894s +3.735s
└─local-fs.target @24.892s
└─run-user-1000.mount @1min 6.484s
└─local-fs-pre.target @6.986s
└─keyboard-setup.service @4.537s +2.449s
└─systemd-journald.socket @4.535s
└─-.mount @4.506s
└─system.slice @4.506s
└─-.slice @4.506s
`
显示samba和NetworkManager-wait-online.service现在不会在引导期间启动，因此快了 1 分钟 10.516s +3.643s 和 37.538s +9.086s。但我仍然得到这个：
$ systemd-analyze
Startup finished in 3.312s (firmware) + 4.447s (loader) + 4.513s (kernel) + 1min 16.469s (userspace) = 1min 28.743s
graphical.target reached after 1min 13.716s in userspace
启动时间仍然接近 3 分钟，
systemd-analyze
但我用时钟测量了 2 百万的启动时间，为什么会有这样的差异？因为samba和NetworkManager-wait-online.service禁用，systemd-analyze应该显示更快的启动时间？
systemd-analyze blame | head -20
`23.031s systemd-journal-flush.service
19.634s dev-sda2.device
14.908s udisks2.service
13.562s ufw.service
11.586s networkd-dispatcher.service
11.428s ModemManager.service
10.517s lightdm.service
10.486s plymouth-quit-wait.service
9.811s snapd.service
8.519s accounts-daemon.service
8.076s dev-loop6.device
7.916s dev-loop3.device
7.779s dev-loop7.device
7.572s dev-loop0.device
7.093s avahi-daemon.service
6.804s dev-loop4.device
6.743s dev-loop1.device
6.692s apparmor.service
6.641s systemd-logind.service
6.641s thermald.service`
