/dev/loop0 100% 这个提示通常意味着在Linux或类Unix系统中，loop设备（也称为loopback设备或loopback文件系统）已经100%被使用了。Loop设备是一种特殊的块设备，它允许用户将文件作为块设备挂载，通常用于挂载磁盘镜像或ISO文件。
可能是由于以下原因之一：
1：挂载的文件或磁盘镜像过大：如果你挂载了一个非常大的文件或磁盘镜像，并且尝试在其中写入大量数据，这可能会导致/dev/loop0空间不足。
2：临时文件或缓存占满空间：某些应用程序或服务可能会使用/dev/loop0来存储临时文件或缓存数据，如果这些文件或数据不断增长并且没有被正确清理，也可能导致空间占满。
3：挂载点或文件系统问题：如果/dev/loop0所挂载的文件系统或挂载点存在问题，例如权限设置不当、文件系统损坏等，也可能导致异常的空间占用。
引起以下问题：
1：写入失败：当 /dev/loop0 空间占满时，任何尝试写入新数据的操作都会失败。这可能导致应用程序或服务无法正常运行，因为它们可能依赖于此设备上的存储空间。
2：性能下降：当文件系统接近满载时，系统的整体性能可能会受到影响。磁盘I/O操作可能会变慢，导致应用程序响应迟缓。
服务中断：如果某些关键服务或应用程序正在使用 /dev/loop0 并且无法写入数据，它们可能会崩溃或停止工作。这可能导致系统中断或3：用户无法访问某些功能。
4：数据丢失风险：在极端情况下，如果 /dev/loop0 上的文件系统因为空间不足而无法正确写入数据，可能会导致数据损坏或丢失。
为了避免这些问题，建议定期监控系统的磁盘使用情况，并及时清理不必要的文件和数据。当发现 /dev/loop0 或其他任何存储设备使用率过高时，应立即采取措施释放空间或扩展存储容量。
解决：sudo apt autoremove --purge snapd
ubuntu@ubuntu:~/Desktop$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 16G 0 16G 0% /dev
tmpfs 3.1G 2.0M 3.1G 1% /run
/dev/sdb4 15G 4.1G 11G 28% /cdrom
/dev/loop0 2.3G 2.3G 0 100% /rofs
/cow 16G 360M 16G 3% /
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 5.0M 8.0K 5.0M 1% /run/lock
tmpfs 16G 0 16G 0% /sys/fs/cgroup
tmpfs 16G 4.0K 16G 1% /tmp
/dev/loop1 128K 128K 0 100% /snap/bare/5
/dev/loop3 347M 347M 0 100% /snap/gnome-3-38-2004/119
/dev/loop2 64M 64M 0 100% /snap/core20/1828
/dev/loop4 92M 92M 0 100% /snap/gtk-common-themes/1535
/dev/loop6 50M 50M 0 100% /snap/snapd/18357
/dev/loop5 46M 46M 0 100% /snap/snap-store/638
tmpfs 3.1G 88K 3.1G 1% /run/user/999
ubuntu@ubuntu:~/Desktop$ sudo apt autoremove --purge snapd
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
snapd*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 171 MB disk space will be freed.
Do you want to continue? [Y/n] Y
(Reading database ... 188767 files and directories currently installed.)
Removing snapd (2.58+20.04) ...
Warning: Stopping snapd.service, but it can still be activated by:
snapd.socket
Processing triggers for mime-support (3.64ubuntu1) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for dbus (1.12.16-2ubuntu2.3) ...
Processing triggers for desktop-file-utils (0.24-1ubuntu3) ...
(Reading database ... 188674 files and directories currently installed.)
Purging configuration files for snapd (2.58+20.04) ...
Stopping snap-bare-5.mount
Stopping unit snap-bare-5.mount
Waiting until unit snap-bare-5.mount is stopped [attempt 1]
snap-bare-5.mount is stopped.
Removing snap bare and revision 5
Removing snap-bare-5.mount
Stopping snap-core20-1828.mount
Stopping unit snap-core20-1828.mount
Waiting until unit snap-core20-1828.mount is stopped [attempt 1]
snap-core20-1828.mount is stopped.
Removing snap core20 and revision 1828
Removing snap-core20-1828.mount
Stopping snap-gnome\x2d3\x2d38\x2d2004-119.mount
Stopping unit snap-gnome\x2d3\x2d38\x2d2004-119.mount
Waiting until unit snap-gnome\x2d3\x2d38\x2d2004-119.mount is stopped [attempt 1]
snap-gnome\x2d3\x2d38\x2d2004-119.mount is stopped.
Removing snap gnome-3-38-2004 and revision 119
Removing snap-gnome\x2d3\x2d38\x2d2004-119.mount
Stopping snap-gtk\x2dcommon\x2dthemes-1535.mount
Stopping unit snap-gtk\x2dcommon\x2dthemes-1535.mount
Waiting until unit snap-gtk\x2dcommon\x2dthemes-1535.mount is stopped [attempt 1]
snap-gtk\x2dcommon\x2dthemes-1535.mount is stopped.
Removing snap gtk-common-themes and revision 1535
Removing snap-gtk\x2dcommon\x2dthemes-1535.mount
Stopping snap-snap\x2dstore-638.mount
Stopping unit snap-snap\x2dstore-638.mount
Waiting until unit snap-snap\x2dstore-638.mount is stopped [attempt 1]
snap-snap\x2dstore-638.mount is stopped.
Removing snap snap-store and revision 638
Removing snap-snap\x2dstore-638.mount
Stopping snap-snapd-18357.mount
Stopping unit snap-snapd-18357.mount
Waiting until unit snap-snapd-18357.mount is stopped [attempt 1]
snap-snapd-18357.mount is stopped.
Removing snap snapd and revision 18357
Removing snap-snapd-18357.mount
Discarding preserved snap namespaces
Final directory cleanup
Removing extra snap-confine apparmor rules
Removing snapd cache
Removing snapd state
ubuntu@ubuntu:~/Desktop$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 16G 0 16G 0% /dev
tmpfs 3.1G 1.9M 3.1G 1% /run
/dev/sdb4 15G 4.1G 11G 28% /cdrom
/dev/loop0 2.3G 2.3G 0 100% /rofs
/cow 16G 360M 16G 3% /
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 5.0M 8.0K 5.0M 1% /run/lock
tmpfs 16G 0 16G 0% /sys/fs/cgroup
tmpfs 16G 4.0K 16G 1% /tmp
tmpfs 3.1G 80K 3.1G 1% /run/user/999