当我关闭运行 Ubuntu 16.04 LTS 的计算机时，需要几秒钟才能看到Reached target Shutdown控制台上显示的最终消息。但是，显示此消息后，需要很长时间才能物理关闭。从，journalctl我观察到 90 秒后显示，30 分钟后（交换停用错误发生后 28:30），它显示和，然后立即最终关闭。30 分钟超时似乎仅在计算机开启一段时间（数小时）后才会发生。如果计算机仅开启了很短的时间（不到一小时），它通常会很快关闭。Reached target Shutdownsystemddev-sda5.swap: Deactivation timed outReached target ShutdownTimed out starting Power-OffForcibly powering off as result of failure
journalctl对于这种情况的最后几行做快速关闭：
dec 04 09:23:54 sjisjka systemd[1]: dev-.bootchart-proc.mount: Mount process exited, code=exited status=32
dec 04 09:23:54 sjisjka systemd[1]: Failed unmounting /dev/.bootchart/proc.
dec 04 09:23:54 sjisjka systemd[1]: Unmounted /run/user/129.
dec 04 09:23:54 sjisjka systemd[1]: Unmounted /run/user/1000.
dec 04 09:23:54 sjisjka systemd[1]: Stopped target Local File Systems (Pre).
dec 04 09:23:54 sjisjka systemd[1]: Stopped Create Static Device Nodes in /dev.
dec 04 09:23:54 sjisjka systemd[1]: Stopped Remount Root and Kernel File Systems.
dec 04 09:23:54 sjisjka systemd[1]: Reached target Shutdown.
dec 04 09:23:57 sjisjka systemd[1]: Deactivated swap /dev/disk/by-uuid/a092fe32-c536-4c0c-bd2e-416f606b2c33.
dec 04 09:23:57 sjisjka systemd[1]: Deactivated swap /dev/disk/by-path/pci-0000:00:1f.5-ata-1-part5.
dec 04 09:23:57 sjisjka systemd[1]: Deactivated swap /dev/disk/by-id/wwn-0x5002538d40d0e7c8-part5.
dec 04 09:23:57 sjisjka systemd[1]: Deactivated swap /dev/disk/by-id/ata-Samsung_SSD_850_EVO_500GB_S2RBNX0H448728M-part5.
dec 04 09:23:57 sjisjka systemd[1]: Deactivated swap /dev/sda5.
dec 04 09:23:57 sjisjka systemd[1]: Reached target Unmount All Filesystems.
dec 04 09:23:57 sjisjka systemd[1]: Reached target Final Step.
dec 04 09:23:57 sjisjka systemd[1]: Starting Power-Off...
dec 04 09:23:57 sjisjka systemd-udevd[13082]: failed to execute '/lib/udev/socket:@/org/freedesktop/hal/udev_event' 'socket:@/org/freedesktop/hal/udev_event': No such file or directory
dec 04 09:23:57 sjisjka systemd-udevd[13079]: Process 'socket:@/org/freedesktop/hal/udev_event' failed with exit code 2.
dec 04 09:23:57 sjisjka systemd[1]: Shutting down.
dec 04 09:23:57 sjisjka systemd-shutdown[1]: Sending SIGTERM to remaining processes...
dec 04 09:23:57 sjisjka systemd-journald[304]: Journal stopped
-- Reboot --
案件的最后几行才不是快速关闭：
dec 05 23:55:06 sjisjka systemd[1]: Stopped LSB: ebtables ruleset management.
dec 05 23:55:06 sjisjka systemd[1]: Stopped target Local File Systems.
dec 05 23:55:06 sjisjka systemd[1]: Unmounting /dev/.bootchart/proc...
dec 05 23:55:06 sjisjka systemd[1]: Unmounting /run/user/129...
dec 05 23:55:06 sjisjka systemd[1]: Unmounted /dev/.bootchart/proc.
dec 05 23:55:06 sjisjka systemd[1]: Unmounted /run/user/129.
dec 05 23:55:06 sjisjka systemd[1]: Stopped target Local File Systems (Pre).
dec 05 23:55:06 sjisjka systemd[1]: Stopped Create Static Device Nodes in /dev.
dec 05 23:55:06 sjisjka systemd[1]: Stopped Remount Root and Kernel File Systems.
dec 05 23:55:06 sjisjka systemd[1]: Reached target Shutdown.
dec 05 23:56:36 sjisjka systemd[1]: dev-sda5.swap: Deactivation timed out. Stopping.
dec 05 23:56:36 sjisjka systemd[1]: Deactivated swap /dev/sda5.
dec 05 23:56:36 sjisjka systemd[1]: dev-sda5.swap: Unit entered failed state.
dec 05 23:56:36 sjisjka systemd-udevd[7031]: failed to execute '/lib/udev/socket:@/org/freedesktop/hal/udev_event' 'socket:@/org/freedesktop/hal/udev_event': No such file or directory
dec 05 23:56:36 sjisjka systemd-udevd[7029]: Process 'socket:@/org/freedesktop/hal/udev_event' failed with exit code 2.
dec 06 00:25:03 sjisjka systemd[1]: poweroff.target: Job poweroff.target/start timed out.
dec 06 00:25:03 sjisjka systemd[1]: Timed out starting Power-Off.
dec 06 00:25:03 sjisjka systemd[1]: poweroff.target: Job poweroff.target/start failed with result 'timeout'.
dec 06 00:25:03 sjisjka systemd[1]: Forcibly powering off as result of failure.
dec 06 00:25:03 sjisjka systemd[1]: Shutting down.
dec 06 00:25:03 sjisjka systemd-shutdown[1]: Sending SIGTERM to remaining processes...
dec 06 00:25:03 sjisjka systemd-journald[298]: Journal stopped
该计算机是 2008 年的戴尔，配备 Intel(R) Core(TM)2 Duo CPU，E7300 @ 2.66GHz。它有 4 GB RAM（4×1GB）和最新的 448 GB SSD 磁盘。
在操作系统关闭所有服务（或声称已关闭）后，哪个进程或组件负责发送“关闭”命令？我该如何调试它，发现它显然无法正常工作？什么原因可能导致这种情况，我该如何解决？在撰写本文时，有Google 搜索中只有 5 条结果对于“启动关机超时”。最有希望的结果是ubuntu 错误报告症状相同，但这种情况似乎与cpufreqd我没有收到的消息有关。还有一个德语 Linux Mint 线程症状不同，没有结论，Redhad 错误描述它与 NFS 相关，但我也没有使用 NFS。其他结果都是没有上下文的原始日志，对我没有任何帮助。