在过去的几个月里，尤其是升级到 Ubuntu 20.04 之后，启动变得非常慢。我今天记录了以下时间：
- 从打开笔记本电脑到屏幕上出现密码请求 - 02:40.24
- 输入密码后，桌面出现 - 01:53.58
以下是有关我的系统的一些信息：
Desktop: Gnome 3.36.9 Distro: Ubuntu 20.04.3 LTS (Focal Fossa)
Type: Laptop System: Dell product: Latitude E6410
Topology: Dual Core model: Intel Core i5 M 560 bits: 64 type: MT MCP
L2 cache: 3072 KiB
跑步后systemd-analyze
Startup finished in 4.884s (kernel) + 2min 8.324s (userspace) = 2min 13.208s
graphical.target reached after 2min 7.779s in userspace
一些输出systemd-analyze blame
1min 14.416s plymouth-quit-wait.service
1min 8.179s fwupd.service
1min 6.091s mysql.service
52.731s snapd.service
41.142s [email protected]
37.991s ua-messaging.service
34.569s vboxdrv.service
32.004s dev-sda5.device
31.959s networkd-dispatcher.service
28.590s [email protected]
24.746s systemd-journal-flush.service
23.763s apport-autoreport.service
23.591s apache2.service
22.546s udisks2.service
18.203s accounts-daemon.service
16.181s dev-loop19.device
16.133s NetworkManager-wait-online.service
15.961s dev-loop12.device
15.744s ModemManager.service
15.728s dev-loop21.device
15.717s dev-loop23.device
15.610s dev-loop25.device
15.307s dev-loop22.device
15.285s dev-loop24.device
15.227s dev-loop13.device
14.943s dev-loop17.device
14.389s dev-loop18.device
14.101s dev-loop4.device
13.544s dev-loop15.device
13.231s dev-loop20.device
13.150s NetworkManager.service
13.043s avahi-daemon.service
12.515s polkit.service
12.434s grub-common.service
12.051s dev-loop7.device
11.738s dev-loop16.device
11.714s dev-loop11.device
11.703s dev-loop9.device
11.687s dev-loop10.device
最后，输出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 @2min 7.779s
└─multi-user.target @2min 7.779s
└─mysql.service @53.227s +1min 6.091s
└─network.target @52.904s
└─NetworkManager.service @39.753s +13.150s
└─dbus.service @39.741s
└─basic.target @39.576s
└─sockets.target @39.576s
└─snapd.socket @39.574s +1ms
└─sysinit.target @39.422s
└─swap.target @39.422s
└─dev-disk-by\x2duuid-30378a1f\x2ddb3d\x2d468b\x2dbc15\x2d5545a99daaaf.swap @39.193s +228ms
└─dev-disk-by\x2duuid-30378a1f\x2ddb3d\x2d468b\x2dbc15\x2d5545a99daaaf.device @39.192s
由于我对 Linux 还不是很熟悉，有人能看出有什么需要修复，以便我可以恢复到合理的启动时间吗？
答案1
这是一个相当简朴的 Ubuntu 20.04
$ systemd-analyze
启动耗时 6.458 秒（固件）+ 4.588 秒（加载器）+ 2.911 秒（内核）+ 9.150 秒（用户空间）= 23.108 秒
用户空间中 9.136 秒后达到 graphic.target
$ systemd-analyze 关键链
在“@”字符后打印单元激活或启动的时间。
设备启动所需的时间打印在“+”字符后面。
graphic.target @9.136s
└─multi-user.target @9.136s
└─kerneloops.service @8.674秒+18毫秒
└─network-online.target @8.672s
└─NetworkManager-wait-online.service @2.341s +6.330s
└─NetworkManager.service @2.224s +115ms
└─dbus.service @2.221s
└─basic.target @2.209秒
└─sockets.target @2.209s
└─snapd.socket @2.207s +1ms
└─sysinit.target @2.201s
└─systemd-timesyncd.service @2.065s +135ms
└─systemd-tmpfiles-setup.service @2.028s +32ms
└─local-fs.target @2.025s
└─run-user-125-gvfs.mount @3.152s
└─run-user-125.mount @2.975s
└─swap.target @2.057秒
└─dev-disk-by\x2duuid-ed163828\x2d666c\x2d4dae\x2db43c\x2dce7dd1d8bdd2.swap @1.987s +69ms
└─dev-disk-by\x2duuid-ed163828\x2d666c\x2d4dae\x2db43c\x2dce7dd1d8bdd2.device @1.983s
我想说的是，您需要查看在启动/登录时需要启动哪些 SW 包。
MySQL 和 Apache 可能会引起你的兴趣。
$ systemd-analyze blame #所有输出 6.777s plymouth-退出-等待.服务 6.330s NetworkManager-wait-online.service 1.640s dev-nvme0n1p3.device 913ms snapd.service 631ms systemd-logind.service 544ms fwupd.服务 458ms dev-loop1.device 391ms dev-loop2.device 333ms udisks2.service 309ms dev-loop5.device 303ms dev-loop3.device 298ms dev-loop4.device 227ms accounts-daemon.service 208ms snap-gnome\x2d3\x2d34\x2d1804-72.mount 206ms snap-snapd-13640.mount 202ms snap-snap\x2dstore-547.mount 197ms systemd-resolved.service 186ms networkd-dispatcher.service 174ms snap-bare-5.mount 172ms snap-gtk\x2dcommon\x2dthemes-1519.mount 137ms upower.服务 135ms systemd-timesyncd.服务 133ms dev-loop0.device 130ms systemd-rfkill.service 118ms snap-core18-2246.mount 117ms systemd-udev-trigger.service 117ms avahi-daemon.service 116ms 蓝牙服务 115ms NetworkManager.service 108ms apparmor.service 105ms polkit.service 99ms systemd-journald.service 89ms 键盘设置服务 86毫秒[电子邮件保护] 86ms switcheroo-control.service 86ms apport.服务 81ms thermald.service 77ms wpa_supplicant.service 77毫秒[电子邮件保护] 77ms systemd-udevd.service 73ms grub-common.service 69ms dev-disk-by\x2duuid-ed163828\x2d666c\x2d4dae\x2db43c\x2dce7dd1d8bdd2.swap 67ms gpu-manager.service 52ms systemd-journal-flush.service 47ms ModemManager.服务 46ms systemd-modules-load.service 44ms snapd.apparmor.service 42ms secureboot-db.service 35毫秒 e2scrub_reap.service 33ms rsyslog.服务 32ms systemd-tmpfiles-setup.service 30ms plymouth-start.service 29ms systemd-fsck@dev-disk-by\x2duuid-32BD\x2d13BA.service 27ms gdm.服务 26毫秒[电子邮件保护] 26ms nvidia-persistenced.service 23ms systemd-random-seed.service 22ms systemd-tmpfiles-clean.service 21ms colord.service 21ms pppd-dns.服务 21ms snapd.seed.service 20ms alsa-restore.service 19ms systemd-backlight@leds:asus::kbd_backlight.service 19ms systemd-sysusers.service 19ms 系统内核跟踪.mount 19ms 系统内核调试.mount 18ms dev-mqueue.mount 18ms dev-hugepages.mount 18ms kerneloops.service 18ms systemd-tmpfiles-setup-dev.service 15ms systemd-remount-fs.service 14毫秒[电子邮件保护] 14ms kmod-静态节点.service 14ms systemd-sysctl.service 12ms systemd-update-utmp.service 11ms plymouth-read-write.service 10毫秒[电子邮件保护] 10ms grub-initrd-fallback.service 9ms systemd-update-utmp-runlevel.service 9ms systemd-用户会话.服务 9ms ufw.服务 8ms systemd-backlight@backlight:intel_backlight.service 7ms rtkit-daemon.service 6ms 启动-efi.mount 6ms 系统文件系统保险丝连接.mount 5ms 系统内核配置.mount 4ms openvpn.服务 3ms setvtrgb.服务 3ms 控制台设置.服务 1ms snapd.socket