我正在尝试从 Ubuntu18 中的 raspbian 中缩小图像文件，使其尺寸变小且易于传输。我正在关注此视频，该视频的人使用以下命令设置循环设备
sudo losetup /dev/loop0 raspbian-20200505.img -o $((532480*512))
但这给了我错误：
losetup: raspbian-20200505.img: failed to set up loop device: Device or resource busy
谁能告诉我这个错误的原因是什么以及我该如何解决它。请帮忙。谢谢
我注意到我的设备在启动时变得越来越慢，即使我有 SSD，所以我试图挖掘它。
首先，我看到文件 resume 中有一个错误，将其更改为 resume=none。我看到了一点推动力。
在更改简历文件（一开始不存在）之前，加载时间为 5 37 秒，这很糟糕。
现在：用户空间 3 分钟 14.290 秒。
systemd-analyze time 892 11:00:03
Startup finished in 7.298s (firmware) + 3.630s (loader) + 2.673s (kernel) + 3min 688ms (userspace) = 3min 14.290s
graphical.target reached after 1min 38.373s in userspace
我试图看看它有什么问题，然后我看到了 dev-loop 设备。我不知道如何处理它，如果我能阻止它们，它是否会影响我的笔记本电脑）
systemd-analyze blame 893 11:00:10
7.517s plymouth-quit-wait.service
6.558s NetworkManager-wait-online.service
2.220s dev-sda6.device
2.053s snapd.service
891ms networkd-dispatcher.service
658ms dev-loop8.device
639ms dev-loop9.device
631ms dev-loop11.device
630ms dev-loop13.device
629ms dev-loop12.device
591ms dev-loop16.device
590ms dev-loop15.device
584ms dev-loop10.device
579ms dev-loop14.device
579ms dev-loop1.device
575ms dev-loop4.device
570ms dev-loop5.device
565ms dev-loop2.device
564ms dev-loop3.device
560ms dev-loop0.device
543ms snap-core18-1705.mount
541ms snap-vlc-1397.mount
540ms snap-heroku-3881.mount
528ms dev-loop7.device
526ms snap-gnome\x2dcharacters-399.mount
522ms systemd-backlight@backlight:intel_backlight.service
518ms dev-loop6.device
493ms dev-loop22.device
491ms dev-loop19.device
490ms dev-loop20.device
475ms dev-loop17.device
462ms dev-loop21.device
461ms snap-gtk\x2dcommon\x2dthemes-1440.mount
459ms dev-loop18.device
455ms systemd-logind.service
445ms snap-postman-102.mount
435ms udisks2.service
402ms snap-gnome\x2dcalculator-544.mount
393ms systemd-rfkill.service
389ms apparmor.service
351ms ModemManager.service
328ms snap-skype-115.mount
318ms upower.service
303ms accounts-daemon.service
293ms snap-core18-1668.mount
291ms systemd-journal-flush.service
287ms keyboard-setup.service
278ms NetworkManager.service
270ms snap-gnome\x2dcalculator-704.mount
263ms snap-musixmatch-18.mount
255ms snap-postman-103.mount
247ms snap-gnome\x2dlogs-81.mount
243ms grub-common.service
241ms snap-gnome\x2dsystem\x2dmonitor-127.mount
237ms snap-core-8689.mount
236ms systemd-udev-trigger.service
231ms plymouth-read-write.service
208ms snap-skype-118.mount
207ms fwupd.service
203ms user@121.service
201ms speech-dispatcher.service
186ms bluetooth.service
184ms snap-hello\x2dworld-29.mount
175ms snap-gtk\x2dcommon\x2dthemes-1474.mount
171ms systemd-journald.service
171ms apport.service
171ms gpu-manager.service
168ms snap-gnome\x2d3\x2d28\x2d1804-116.mount
156ms snap-core-8935.mount
155ms snap-gnome\x2dcharacters-495.mount
150ms wpa_supplicant.service
141ms snap-gnome\x2dlogs-93.mount
137ms snap-gnome\x2dsystem\x2dmonitor-135.mount
117ms avahi-daemon.service
114ms thermald.service
102ms systemd-resolved.service
99ms packagekit.service
92ms systemd-udevd.service
86ms systemd-timesyncd.service
84ms user@1000.service
80ms systemd-backlight@leds:dell::kbd_backlight.service
77ms rsyslog.service
76ms bolt.service
74ms snapd.seeded.service
73ms polkit.service
73ms alsa-restore.service
49ms systemd-modules-load.service
49ms plymouth-start.service
48ms gdm.service
43ms systemd-fsck@dev-disk-by\x2duuid-105D\x2d71B7.service
41ms networking.service
40ms systemd-sysctl.service
35ms colord.service
35ms pppd-dns.service
33ms dns-clean.service
32ms systemd-tmpfiles-setup.service
27ms dev-disk-by\x2duuid-606cd432\x2d01a6\x2d4c87\x2dbdcf\x2d22c1d60
25ms dev-mqueue.mount
24ms systemd-tmpfiles-setup-dev.service
24ms systemd-remount-fs.service
24ms kerneloops.service
22ms kmod-static-nodes.service
21ms ufw.service
14ms boot-efi.mount
14ms sys-fs-fuse-connections.mount
13ms ureadahead-stop.service
12ms sys-kernel-config.mount
11ms systemd-update-utmp-runlevel.service
11ms systemd-update-utmp.service
9ms sys-kernel-debug.mount
8ms dev-hugepages.mount
8ms systemd-user-sessions.service
8ms rtkit-daemon.service
7ms console-setup.service
7ms systemd-random-seed.service
5ms setvtrgb.service
2ms snapd.socket
lines 95-117/117 (END)
我从 ubuntu 中删除了 snap 以查看对启动的影响。
systemd-analyze blame 973 09:42:30
29.641s apt-daily.service
8.675s plymouth-quit-wait.service
7.869s fstrim.service
6.578s NetworkManager-wait-online.service
6.166s apt-daily-upgrade.service
2.297s dev-sda6.device
919ms motd-news.service
722ms systemd-journal-flush.service
711ms systemd-backlight@backlight:intel_backlight.service
485ms upower.service
478ms apparmor.service
469ms networkd-dispatcher.service
426ms packagekit.service
409ms udisks2.service
394ms systemd-logind.service
380ms apport.service
379ms plymouth-read-write.service
348ms grub-common.service
316ms systemd-udevd.service
298ms systemd-rfkill.service
287ms speech-dispatcher.service
265ms ModemManager.service
252ms NetworkManager.service
245ms keyboard-setup.service
212ms fwupd.service
202ms systemd-udev-trigger.service
200ms user@121.service
191ms bluetooth.service
157ms systemd-journald.service
143ms avahi-daemon.service
137ms thermald.service
133ms alsa-restore.service
127ms bolt.service
118ms rng-tools.service
118ms accounts-daemon.service
105ms gpu-manager.service
100ms gdm.service
95ms pppd-dns.service
92ms plymouth-start.service
89ms systemd-timesyncd.service
85ms user@1000.service
81ms wpa_supplicant.service
67ms systemd-resolved.service
66ms colord.service
59ms systemd-modules-load.service
55ms systemd-tmpfiles-setup-dev.service
54ms kerneloops.service
48ms systemd-fsck@dev-disk-by\x2duuid-105D\x2d71B7.service
48ms systemd-backlight@leds:dell::kbd_backlight.service
45ms dns-clean.service
44ms rsyslog.service
40ms networking.service
38ms dev-disk-by\x2duuid-606cd432\x2d01a6\x2d4c87\x2dbdcf\x2d22c1d60
35ms systemd-random-seed.service
34ms polkit.service
28ms systemd-remount-fs.service
26ms systemd-sysctl.service
26ms systemd-tmpfiles-setup.service
20ms systemd-user-sessions.service
20ms dev-mqueue.mount
19ms kmod-static-nodes.service
18ms ufw.service
17ms systemd-update-utmp.service
16ms dev-hugepages.mount
16ms ureadahead-stop.service
13ms sys-kernel-debug.mount
13ms sys-fs-fuse-connections.mount
12ms systemd-update-utmp-runlevel.service
11ms boot-efi.mount
9ms sys-kernel-config.mount
7ms console-setup.service
5ms rtkit-daemon.service
4ms setvtrgb.service
systemd-analyze critical-chain 975 09:44:43
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 39.346s
└─multi-user.target @1min 39.346s
└─kerneloops.service @1min 37.195s +54ms
└─network-online.target @1min 37.193s
└─NetworkManager-wait-online.service @1min 30.614s +6.578s
└─NetworkManager.service @1min 30.354s +252ms
└─dbus.service @1min 30.310s
└─basic.target @1min 30.238s
└─sockets.target @1min 30.238s
└─dbus.socket @1min 30.235s
└─sysinit.target @1min 30.229s
└─apparmor.service @2.594s +478ms
└─local-fs.target @2.585s
└─run-user-1000-gvfs.mount @1min 56.316s
└─run-user-1000.mount @1min 55.465s
└─local-fs-pre.target @454ms
└─keyboard-setup.service @209ms +245ms
└─systemd-journald.socket @196ms
└─system.slice @195ms
└─-.slice @192ms
我有一堆带有 .vcf 后缀的文件，逗号分隔并包含“，如下所示
"","CHROM","POS","ID","REF","ALT","QUAL","FILTER","INFO","FORMAT","NORMAL","TUMOR","Depth","DistanceToAlignmentEnd","DistanceToAlignmentEndMAD","DistanceToAlignmentEndMedian","HomopolymerLength","LowMapQual","MMQSDiff","MapQualDiff","MapQualDiffMedian","NT","QSS","QSS_NT","ReadCount","ReadCountControl","Repeat","SGT","SNVCluster10","SNVCluster100","SNVCluster20","SNVCluster5","SNVCluster50","SOMATIC","StrandBias","TQSS","TQSS_NT","VariantAlleleCount","VariantAlleleCountControl","VariantAlleleFrequency","VariantBaseQual","VariantBaseQualMedian","VariantMMQS","VariantMapQual","VariantMapQualMedian","VariantStrandBias","normal","tumour","N_DP","N_FDP","N_SDP","N_SUBDP","T_DP","T_FDP","T_SDP","T_SUBDP","T_REF_COUNT","T_ALT_COUNT","N_REF_COUNT","N_ALT_COUNT","T_VAF","N_VAF","N_AU_1","N_AU_2","N_CU_1","N_CU_2","N_GU_1","N_GU_2","N_TU_1","N_TU_2","T_AU_1","T_AU_2","T_CU_1","T_CU_2","T_GU_1","T_GU_2","T_TU_1","T_TU_2"
"1","chr1","11195689",".","C","G",".","PASS","Depth=83;DistanceToAlignmentEnd=38.75;DistanceToAlignmentEndMAD=9.00;DistanceToAlignmentEndMedian=37.50;HomopolymerLength=2;LowMapQual=0.00;MMQSDiff=136.94;MapQualDiff=-8.750e-01;MapQualDiffMedian=0.00;NT=ref;QSS=16;QSS_NT=16;ReadCount=83;ReadCountControl=49;Repeat=0;SGT=CC->CG;SNVCluster10=0;SNVCluster100=2;SNVCluster20=1;SNVCluster5=0;SNVCluster50=2;SOMATIC;StrandBias=0.482;TQSS=1;TQSS_NT=1;VariantAlleleCount=4;VariantAlleleCountControl=1;VariantAlleleFrequency=0.048;VariantBaseQual=40.00;VariantBaseQualMedian=41.00;VariantMMQS=157.25;VariantMapQual=59.00;VariantMapQualMedian=60.00;VariantStrandBias=0.250","DP:FDP:SDP:SUBDP:AU:CU:GU:TU","49:1:0:0:0,0:47,48:1,1:0,0","82:0:0:0:0,0:78,79:4,4:0,0","83","38.75","9","37.5","2","0","136.94","-0.875","0","ref","16","16","83","49","0","CC->CG","0","2","1","0","2","SOMATIC","0.482","1","1","4","1","0.048","40","41","157.25","59","60","0.25","list(DP = ""49"", FDP = ""1"", SDP = ""0"", SUBDP = ""0"", AU = ""0,0"", CU = ""47,48"", GU = ""1,1"", TU = ""0,0"")","list(DP = ""82"", FDP = ""0"", SDP = ""0"", SUBDP = ""0"", AU = ""0,0"", CU = ""78,79"", GU = ""4,4"", TU = ""0,0"")","49","1","0","0","82","0","0","0","78","4","47","1","0.0487804878048781","0.0208333333333333","0","0","47","48","1","1","0","0","0","0","78","79","4","4","0","0"
如何将逗号空间转换为制表符，删除“，删除第一列，最后将清理后的文件保存为 .txt，并使用匹配的原始文件的基本名称？
在一个文件夹中有一组匹配的文件，每对文件的名称是这样的，带有一个基本名称，例如
LP6005334-DNA_H01_vs_LP6005333-DNA_H01.passed.somatic.indels.vcf.parsed.txt
和
LP6005334-DNA_H01_vs_LP6005333-DNA_H01.passed.somatic.indels.vcf_fixed_vcf.txt.hg19_multianno.txt
我如何columns 5th and 6th从文件passed.somatic.indels.vcf.parsed名中提取文件并将这些列附加到匹配的文件 ( ) 中，返回带有基本名称( )passed.somatic.indels.vcf_fixed_vcf.txt.hg19_multianno的输出.txtLP6005334-DNA_H01_vs_LP6005333-DNA_H01
为了切割我所做的列
[
fi1d18@cyan01 folder]$ for f in *.passed.somatic.indels.vcf.parsed.txt; do awk '{print $5,$6}' $f > $out
> done;
-bash: $out: ambiguous redirect
此后我不知道如何找到匹配的查找并将剪切列附加到
这是一对这些文件的链接
和
在我的 Ubuntu 桌面上，该命令fdisk -l显示 /dev/loopX up to /dev/loop23. 我在 Ubuntu 18.04 LTS 上使用 gnome-fallback。
我想知道这些可能对操作系统的性能和稳定性产生什么影响，如果它们只是多余的，我该如何删除它们？
root@pc5:~# fdisk -l
...
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop15: 3.7 MiB, 3821568 bytes, 7464 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop16: 54.6 MiB, 57274368 bytes, 111864 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop17: 140.7 MiB, 147501056 bytes, 288088 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop18: 14.8 MiB, 15462400 bytes, 30200 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop19: 42.8 MiB, 44879872 bytes, 87656 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop20: 54.5 MiB, 57151488 bytes, 111624 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop21: 4.2 MiB, 4403200 bytes, 8600 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop22: 153.5 MiB, 160935936 bytes, 314328 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/loop23: 140.7 MiB, 147501056 bytes, 288088 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
输出df：
Filesystem 1K-blocks Used Available Use% Mounted on
udev 8128184 0 8128184 0% /dev
tmpfs 1630464 3716 1626748 1% /run
/dev/sda2 229184876 63255488 154217748 30% /
tmpfs 8152300 142672 8009628 2% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 8152300 0 8152300 0% /sys/fs/cgroup
/dev/loop2 160512 160512 0 100% /snap/gnome-3-28-1804/110
/dev/loop3 4352 4352 0 100% /snap/gnome-calculator/544
/dev/loop0 3840 3840 0 100% /snap/gnome-system-monitor/111
/dev/loop4 91264 91264 0 100% /snap/core/8039
/dev/loop1 1024 1024 0 100% /snap/gnome-logs/81
/dev/loop6 87936 87936 0 100% /snap/shotcut/55
/dev/loop5 406528 406528 0 100% /snap/redis-desktop-manager/332
/dev/loop8 91264 91264 0 100% /snap/core/8213
/dev/loop7 406656 406656 0 100% /snap/redis-desktop-manager/335
/dev/loop9 15104 15104 0 100% /snap/gnome-characters/367
/dev/loop11 157184 157184 0 100% /snap/chromium/949
/dev/loop12 87808 87808 0 100% /snap/shotcut/53
/dev/loop13 1024 1024 0 100% /snap/gnome-logs/73
/dev/loop14 45312 45312 0 100% /snap/gtk-common-themes/1353
/dev/loop16 55936 55936 0 100% /snap/core18/1279
/dev/loop15 3840 3840 0 100% /snap/gnome-system-monitor/107
/dev/loop10 159872 159872 0 100% /snap/gnome-3-28-1804/91
/dev/loop17 144128 144128 0 100% /snap/gnome-3-26-1604/97
/dev/sda1 523248 6232 517016 2% /boot/efi
/dev/loop18 15104 15104 0 100% /snap/gnome-characters/359
/dev/loop19 43904 43904 0 100% /snap/gtk-common-themes/1313
/dev/loop20 55936 55936 0 100% /snap/core18/1265
/dev/loop21 4352 4352 0 100% /snap/gnome-calculator/536
/dev/loop22 157184 157184 0 100% /snap/chromium/958
/dev/loop23 144128 144128 0 100% /snap/gnome-3-26-1604/98
/dev/sdb1 492127240 409174612 57930932 88% /home
tmpfs 1630460 16 1630444 1% /run/user/121
tmpfs 1630460 140 1630320 1% /run/user/1001
tmpfs 1630460 0 1630460 0% /run/user/0
我正在使用以下命令为 VM 原始映像备份文件设置循环设备：
sudo losetup /dev/loop0 "/home/asus/VirtualBox VMs/Windows RAW/Windows 10.img"
它工作正常。
$ losetup -l
NAME SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE DIO LOG-SEC
/dev/loop0 0 0 0 0 /home/asus/VirtualBox VMs/Windows RAW/Windows 10.img 0 512
但我想让这个更改永久化，所以我创建了这个.sevice在启动时运行：
$ cat /etc/systemd/system/loops-setup.service
[Unit]
Description=Setup loop devices
DefaultDependencies=no
Conflicts=umount.target
Before=local-fs.target
After=systemd-udev-settle.service
Required=systemd-udev-settle.service
[Service]
Type=oneshot
ExecStart=/sbin/losetup /dev/loop0 "/home/asus/VirtualBox VMs/Windows RAW/Windows 10.img"
ExecStop=/sbin/losetup -d /dev/loop0
TimeoutSec=60
RemainAfterExit=yes
[Install]
WantedBy=local-fs.target
Also=systemd-udev-settle.service
此服务也可以手动启动：
sudo systemctl start loops-setup
但它在启动时无法启动，并显示此错误：
May 11 19:57:17 ubuntu losetup[308]: losetup: /dev/loop0: failed to set up loop device: No such file or directory
我猜是因为服务的层次结构，我应该改变Before和After选择，但我不知道该怎么做。
提前致谢。
我在 Ubuntu 19.04 中也有同样的问题（在 16.04 中恢复了，但删除了整个快照）。
我无法删除一堆快照图像，因为我不确定是否需要它们（例如 Yaru 主题等...）
有什么想法可以将它们从系统监视器中隐藏吗？
当我检查系统的启动日志时，我注意到每个启动都dev-loopx.device需要 3-5 秒的时间，并且在我的启动过程中我总共有 20 个这样的 loopx 设备排队，这最终会减慢我的启动速度。
要获取有关这些 loopx 设备的更多详细信息，我运行了以下命令
$ df -a -h -T
输出中最重要的部分是：
为什么某些应用程序（或其中的一部分）在启动过程中被加载，而我什至没有在每个会话中使用它们？
例如，gaome-calculator应用程序、gtk-common-themes、gnome-system-monitor。
为什么某些应用程序有多个条目（每个应用程序都需要 3-5 秒，甚至更多）？
当我不经常使用相关的应用程序/服务时，如何禁用和/或删除其中一些 loopx 设备？这肯定会加快我的启动过程！
非常感谢任何帮助和指导。
阿巴斯。
在我的计算机上，如果我 ping 与我的网卡关联的地址（enp0s31f6 - 192.168.1.15），则环回设备将是答案实际来自的设备。
我知道环回设备是什么，但是为什么会存在这种关系呢？这是因为在每种情况下都必须有一个输出接口？
使用 列出块后lsblk，我发现列出了 14 个外观块，从循环 0 到循环 13。
me@alpha:~$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 87.9M 1 loop /snap/core/5662
loop1 7:1 0 140.7M 1 loop /snap/gnome-3-26-1604/74
loop2 7:2 0 3.7M 1 loop /snap/gnome-system-monitor/57
loop3 7:3 0 140.9M 1 loop /snap/gnome-3-26-1604/70
loop4 7:4 0 34.6M 1 loop /snap/gtk-common-themes/818
loop5 7:5 0 42.1M 1 loop /snap/gtk-common-themes/701
loop6 7:6 0 89.5M 1 loop /snap/core/6130
loop7 7:7 0 2.3M 1 loop /snap/gnome-calculator/238
loop8 7:8 0 130.2M 1 loop /snap/gnome-3-28-1804/4
loop9 7:9 0 14.5M 1 loop /snap/gnome-logs/45
loop10 7:10 0 13M 1 loop /snap/gnome-characters/124
loop11 7:11 0 53.7M 1 loop /snap/core18/536
loop12 7:12 0 13M 1 loop /snap/gnome-characters/139
loop13 7:13 0 2.3M 1 loop /snap/gnome-calculator/260
sda 8:0 0 113G 0 disk
├─sda1 8:1 0 512M 0 part /boot/efi
└─sda2 8:2 0 112.5G 0 part /
但是，当我列出 usingls /dev和 find blocks usinggrep 'loop'时，我发现列出了 15 个块，并显示了一个额外的块loop14。
me@alpha:~$ ls /dev | grep 'loop'
loop0
loop1
loop10
loop11
loop12
loop13
loop14
loop2
loop3
loop4
loop5
loop6
loop7
loop8
loop9
loop-control
为什么loop14没有列出来lsblk？