我从 18.04 升级到 20.04，并且还拥有最新的操作系统更新。
问题：即使我没有运行前台应用程序或任何重型服务，在我选择并确认“关机”后，也需要 30 秒的时间才能真正开始关机序列。
同样，当我重新启动时，戴尔徽标闪烁完毕后，Ubuntu 相关的启动消息需要经过 15 秒才开始显示。
我在 Ubuntu 18.04 中没有遇到这样的问题。
我怀疑这可能是因为我选择升级；全新安装 20.04 不是一个选项。
关闭部分更新
在15:30:00我通过 Unity GUI 确认关机后。请注意15:30:04和之间的巨大差距15:30:28。这是我每次关机时都会遇到的“30 秒”延迟。到15:30:34整个关机完成时。
我下一步应该检查什么？
Mar 15 15:28:59 dart unity-panel-ser[2698]: menus_destroyed: assertion 'IS_WINDOW_MENU(wm)' failed
Mar 15 15:30:01 dart CRON[6019]: (root) CMD ([ -x /etc/init.d/anacron ] && if [ ! -d /run/systemd/system ]; then /usr/sbin/invoke-rc.d anacron start >/dev/null; fi)
Mar 15 15:30:04 dart unity-panel-ser[2698]: menus_destroyed: assertion 'IS_WINDOW_MENU(wm)' failed
Mar 15 15:30:04 dart gnome-session[2557]: gnome-session-binary[2557]: WARNING: Failed to get delay inhibitor: GDBus.Error:org.freedesktop.login1.OperationInProgress: The operation inhibition has been requested for is already running
Mar 15 15:30:04 dart gnome-session-binary[2557]: WARNING: Failed to get delay inhibitor: GDBus.Error:org.freedesktop.login1.OperationInProgress: The operation inhibition has been requested for is already running
Mar 15 15:30:04 dart gnome-session-binary[2557]: Entering running state
Mar 15 15:30:04 dart unity-panel-ser[2698]: Getting layout failed: GDBus.Error:org.freedesktop.DBus.Error.UnknownObject: No such object path '/MenuBar/1'
Mar 15 15:30:04 dart systemd[1]: unattended-upgrades.service: Succeeded.
Mar 15 15:30:28 dart wpa_supplicant[915]: wlp1s0: CTRL-EVENT-BEACON-LOSS
Mar 15 15:30:28 dart whoopsie[2125]: [15:30:28] Cannot reach: https://daisy.ubuntu.com
Mar 15 15:30:28 dart whoopsie[2125]: [15:30:28] offline
Mar 15 15:30:28 dart whoopsie[2125]: [15:30:28] Cannot reach: https://daisy.ubuntu.com