![为什么Ubuntu桌面版20.04的启动速度非常慢[需要大约3分钟才能登录屏幕]？](/0.jpg)
我已经尝试了一些调整，比如：
移除/禁用服务，
检查硬盘的iostat [平均读取速率约为120 MB/s]。
一切看起来都很正常。但是启动仍然需要大约3分钟。
systemd-analyze plot的输出可以在这个链接中找到。
systemd-analyze blame的输出：
2min 140ms plymouth-quit-wait.service
31.766s systemd-journal-flush.service
28.994s dev-sdb1.device
27.573s snapd.seeded.service
25.841s udisks2.service
25.712s snapd.service
24.896s networkd-dispatcher.service
22.360s accounts-daemon.service
16.608s dev-loop15.device
16.508s dev-loop13.device
15.523s dev-loop5.device
15.307s dev-loop7.device
15.283s dev-loop8.device
15.229s dev-loop12.device
14.963s dev-loop6.device
14.900s polkit.service
14.875s dev-loop14.device
14.799s dev-loop0.device
14.478s avahi-daemon.service
14.418s NetworkManager.service
14.074s switcheroo-control.service
14.067s thermald.service
14.063s wpa_supplicant.service
14.062s systemd-logind.service
13.809s dev-loop1.device
13.633s dev-loop9.device
12.690s dev-loop10.device
12.456s dev-loop11.device
12.424s dev-loop2.device
11.756s dev-loop3.device
11.460s dev-loop4.device
9.932s ModemManager.service
9.213s systemd-udevd.service
8.774s NetworkManager-wait-online.service
8.357s smartmontools.service
7.584s ufw.service
6.966s systemd-resolved.service
6.229s gpu-manager.service
6.220s grub-initrd-fallback.service
5.772s grub-common.service
5.518s apport.service
5.455s apparmor.service
5.176s lm-sensors.service
5.144s rsyslog.service
5.013s kexec.service
4.749s rc.local.service
3.761s hddtemp.service
3.399s networking.service
3.354s e2scrub_reap.service
3.320s monopd.service
3.020s sysstat.service
2.286s snap-core-9289.mount
2.233s snapd.apparmor.service
1.877s systemd-sysusers.service
1.834s binfmt-support.service
1.650s snap-core-9436.mount
1.608s snap-core18-1705.mount
1.581s snap-core18-1754.mount
1.571s gdm.service
1.560s apt-daily.service
1.536s snap-core20-634.mount
1.510s inetd.service
1.492s snap-electron\x2dmail-24.mount
1.491s snap-electron\x2dmail-25.mount
1.474s systemd-modules-load.service
1.463s snap-gimp-273.mount
1.462s snap-gimp-281.mount
1.386s snap-gnome\x2d3\x2d34\x2d1804-36.mount
1.284s ssh.service
1.254s kerneloops.service
1.208s user@119.service
1.192s dev-disk-by\x2duuid-820bee40\x2d75ec\x2d4794\x2daf59\x2d497ba69ebbe8.swap
1.180s systemd-timesyncd.service
1.162s setvtrgb.service
1.135s snap-gtk2\x2dcommon\x2dthemes-13.mount
1.021s systemd-sysctl.service
990ms keyboard-setup.service
981ms upower.service
732ms systemd-random-seed.service
668ms modprobe@drm.service
666ms systemd-journald.service
607ms systemd-tmpfiles-setup-dev.service
601ms dev-hugepages.mount
600ms dev-mqueue.mount
600ms sys-kernel-debug.mount
599ms sys-kernel-tracing.mount
523ms dns-clean.service
510ms console-setup.service
499ms systemd-tmpfiles-setup.service
476ms snap-gtk2\x2dcommon\x2dthemes-9.mount
441ms kmod-static-nodes.service
428ms atd.service
427ms atieventsd.service
404ms colord.service
396ms snap-gtk\x2dcommon\x2dthemes-1502.mount
343ms pppd-dns.service
297ms systemd-udev-trigger.service
288ms user@1000.service
271ms snap-snap\x2dstore-415.mount
243ms snap-snap\x2dstore-467.mount
189ms snap-gtk\x2dcommon\x2dthemes-1506.mount
173ms ifupdown-pre.service
157ms plymouth-start.service
144ms alsa-restore.service
112ms systemd-remount-fs.service
88ms openvpn.service
78ms systemd-user-sessions.service
55ms systemd-update-utmp.service
53ms finalrd.service
51ms systemd-tmpfiles-clean.service
49ms rtkit-daemon.service
41ms proc-sys-fs-binfmt_misc.mount
24ms user-runtime-dir@119.service
19ms user-runtime-dir@1000.service
11ms plymouth-read-write.service
11ms systemd-update-utmp-runlevel.service
11ms resolvconf-pull-resolved.service
11ms kexec-load.service
3ms sys-fs-fuse-connections.mount
3ms sys-kernel-config.mount
980us snapd.socket
硬件信息：
*-memory
description: System memory
physical id: 0
size: 16GiB
*-cpu
product: AMD FX(tm)-8350 Eight-Core Processor
vendor: Advanced Micro Devices [AMD]
physical id: 1
bus info: cpu@0
size: 1399MHz
capacity: 4GHz
*-display
description: VGA compatible controller
product: Baffin [Radeon RX 460/560D / Pro 450/455/460/555/555X/560/560X]
vendor: Advanced Micro Devices, Inc. [AMD/ATI]
physical id: 0
bus info: pci@0000:01:00.0
version: e5
width: 64 bits
clock: 33MHz
capabilities: vga_controller bus_master cap_list rom
configuration: driver=amdgpu latency=0
cat /etc/default/grub的输出结果
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'
GRUB_DEFAULT=0
#GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="crashkernel=2G-6G:256M,6G-8G:512M,8G-:768M"
GRUB_CMDLINE_LINUX="quiet splash noresume"
# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"
# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console
# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480
# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true
# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"
# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"
注意：
多年前，这是一个全新的安装（Ubuntu LTS 12.04或14.04，我现在记不清了）。然后每两年使用sudo do-release-upgrade进行最新LTS的更新。
最初它运行在不同的硬件配置上
Intel Core 2双核处理器
华硕主板。
4 GB RAM。
然后它变成了当前的配置
编辑：根据@heynnema的要求进行更新。
$ free -h
total used free shared buff/cache available
Mem: 15Gi 763Mi 12Gi 34Mi 2.0Gi 14Gi
Swap: 3.4Gi 0B 3.4Gi
$ grep -i swap /etc/fstab
# swap was on /dev/sda4 during installation
UUID=820bee40-75ec-4794-af59-497ba69ebbe8 none swap sw 0 0
#/dev/sdc2: UUID="820bee40-75ec-4794-af59-497ba69ebbe8" TYPE="swap" PARTUUID="000de4b8-02"
$ sudo blkid
[sudo] password for sourav:
/dev/sdb1: UUID="6955c8fd-22d3-4b9b-8a29-f98cec0419bb" TYPE="ext4" PARTUUID="000de4b8-01"
/dev/loop0: TYPE="squashfs"
/dev/loop1: TYPE="squashfs"
/dev/loop2: TYPE="squashfs"
/dev/loop3: TYPE="squashfs"
/dev/loop4: TYPE="squashfs"
/dev/loop5: TYPE="squashfs"
/dev/loop6: TYPE="squashfs"
/dev/loop7: TYPE="squashfs"
/dev/sdd: UUID="f836547b-4a89-7446-abac-281f4559fb1e" UUID_SUB="390af95a-5039-db0b-4e20-d50b472d70cf" LABEL="ubuntu:0" TYPE="linux_raid_member"
/dev/sdb2: UUID="820bee40-75ec-4794-af59-497ba69ebbe8" TYPE="swap" PARTUUID="000de4b8-02"
/dev/sdb3: LABEL="DATA_790" UUID="201855474559DE32" TYPE="ntfs" PTTYPE="atari" PARTUUID="000de4b8-03"
/dev/sdb5: UUID="1cdafd4a-1908-4bff-be5c-6ecfe722f53b" TYPE="ext4" PARTUUID="000de4b8-05"
/dev/sdb6: UUID="C7A7-EC12" TYPE="vfat" PARTUUID="000de4b8-06"
/dev/sda: UUID="f836547b-4a89-7446-abac-281f4559fb1e" UUID_SUB="272a4d7f-bd7f-3a05-b9be-143179b4731c" LABEL="ubuntu:0" TYPE="linux_raid_member"
/dev/sdc: UUID="f836547b-4a89-7446-abac-281f4559fb1e" UUID_SUB="42ab19e9-932b-6318-c23f-2c6f7fb9e48d" LABEL="ubuntu:0" TYPE="linux_raid_member"
/dev/md127p1: LABEL="DATA_100G" UUID="258b4ae7-f26d-4648-a332-105d71998b40" TYPE="ext4" PARTUUID="7b1fc87a-01"
/dev/md127p3: LABEL="DATA_1.8T" UUID="796B821272CAD4DC" TYPE="ntfs" PTTYPE="atari" PARTUUID="7b1fc87a-03"
/dev/md127p5: UUID="e9918fc1-6f8e-4c37-9b60-0d7342d46f07" TYPE="swap" PARTUUID="7b1fc87a-05"
/dev/loop8: TYPE="squashfs"
/dev/loop9: TYPE="squashfs"
/dev/loop10: TYPE="squashfs"
/dev/loop11: TYPE="squashfs"
/dev/loop12: TYPE="squashfs"
/dev/loop13: TYPE="squashfs"
/dev/loop14: TYPE="squashfs"
/dev/loop15: TYPE="squashfs"
$ cat /etc/initramfs-tools/conf.d/resume
RESUME=UUID=820bee40-75ec-4794-af59-497ba69ebbe8
$ sudo lshw -C memory
*-firmware
description: BIOS
vendor: American Megatrends Inc.
physical id: 0
version: V1.4
date: 12/24/2015
size: 64KiB
capacity: 8MiB
capabilities: pci upgrade shadowing cdboot bootselect socketedrom edd int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer acpi usb biosbootspecification uefi
*-cache:0
description: L1 cache
physical id: 5
slot: L1-Cache
size: 384KiB
capacity: 384KiB
clock: 1GHz (1.0ns)
capabilities: pipeline-burst internal write-back unified
configuration: level=1
*-cache:1
description: L2 cache
physical id: 6
slot: L2-Cache
size: 8MiB
capacity: 8MiB
clock: 1GHz (1.0ns)
capabilities: pipeline-burst internal write-back unified
configuration: level=2
*-cache:2
description: L3 cache
physical id: 7
slot: L3-Cache
size: 8MiB
capacity: 8MiB
clock: 1GHz (1.0ns)
capabilities: pipeline-burst internal write-back unified
configuration: level=3
*-memory
description: System Memory
physical id: 27
slot: System board or motherboard
size: 16GiB
*-bank:0
description: DIMM DDR3 Synchronous Unbuffered (Unregistered) 800 MHz (1.2 ns)
product: TS1GLK64V6H
vendor: Transcend
physical id: 0
serial: 000ABB8B
slot: A1_DIMM0
size: 8GiB
width: 64 bits
clock: 800MHz (1.2ns)
*-bank:1
description: DIMMProject-Id-Version: lshwReport-Msgid-Bugs-To: FULL NAME
product: Array1_PartNumber1
vendor: A1_Manufacturer1
physical id: 1
serial: A1_SerNum1
slot: A1_DIMM1
*-bank:2
description: DIMM DDR3 Synchronous Unbuffered (Unregistered) 800 MHz (1.2 ns)
product: V01L3LF8GB52852816
vendor: Undefined
physical id: 2
serial: 00000000
slot: A1_DIMM2
size: 8GiB
width: 64 bits
clock: 800MHz (1.2ns)
*-bank:3
description: DIMMProject-Id-Version: lshwReport-Msgid-Bugs-To: FULL NAME
product: Array1_PartNumber3
vendor: A1_Manufacturer3
physical id: 3
serial: A1_SerNum3
slot: A1_DIMM3
附加信息
$ lsblk
loop0 7:0 0 97M 1 loop /snap/core/9289
loop1 7:1 0 55M 1 loop /snap/core18/1705
loop2 7:2 0 96.5M 1 loop /snap/core/9436
loop3 7:3 0 55M 1 loop /snap/core18/1754
loop4 7:4 0 61M 1 loop /snap/core20/634
loop5 7:5 0 164M 1 loop /snap/electron-mail/24
loop6 7:6 0 164.6M 1 loop /snap/electron-mail/25
loop7 7:7 0 176.4M 1 loop /snap/gimp/281
loop8 7:8 0 255.6M 1 loop /snap/gnome-3-34-1804/36
loop9 7:9 0 175.9M 1 loop /snap/gimp/273
loop10 7:10 0 62.1M 1 loop /snap/gtk-common-themes/1506
loop11 7:11 0 132K 1 loop /snap/gtk2-common-themes/9
loop12 7:12 0 54.8M 1 loop /snap/gtk-common-themes/1502
loop13 7:13 0 49.8M 1 loop /snap/snap-store/467
loop14 7:14 0 43.2M 1 loop /snap/snap-store/415
loop15 7:15 0 140K 1 loop /snap/gtk2-common-themes/13
sda 8:0 1 931.5G 0 disk
└─md127 9:127 0 1.8T 0 raid5
├─md127p1 259:0 0 93.1G 0 part
├─md127p2 259:1 0 1K 0 part
├─md127p3 259:2 0 1.7T 0 part
└─md127p5 259:3 0 4.7G 0 part
sdb 8:16 1 931.5G 0 disk
├─sdb1 8:17 1 95.4G 0 part /
├─sdb2 8:18 1 3.4G 0 part [SWAP]
├─sdb3 8:19 1 731.2G 0 part
├─sdb4 8:20 1 1K 0 part
├─sdb5 8:21 1 100.6G 0 part
└─sdb6 8:22 1 992M 0 part
sdc 8:32 1 931.5G 0 disk
└─md127 9:127 0 1.8T 0 raid5
├─md127p1 259:0 0 93.1G 0 part
├─md127p2 259:1 0 1K 0 part
├─md127p3 259:2 0 1.7T 0 part
└─md127p5 259:3 0 4.7G 0 part
sdd 8:48 1 931.5G 0 disk
└─md127 9:127 0 1.8T 0 raid5
├─md127p1 259:0 0 93.1G 0 part
├─md127p2 259:1 0 1K 0 part
├─md127p3 259:2 0 1.7T 0 part
└─md127p5 259:3 0 4.7G 0 part
解决方案：对于这个问题，plymouth是罪魁祸首。感谢@heynnema！
详细的systemd-analyze plot在移除plymouth之前（约188秒）和之后（约45秒）的链接和链接
故障排除期间进行的其他更改：
更新了/etc/default/grub文件，包括：
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
移除了psensor：$ sudo apt remove psensor
仅保留核心的snap软件包（core, core18, core20, gnome-3-34-1804, gtk-common-themes, gtk2-common-themes, snap-store）