a system service that allows importing, exporting and downloading of disk images. It provides the implementation for importctl(1)'s pull-raw, pull-tar, import-raw, import-tar, import-fs, export-raw, and export-tar commands. All hail Lennart Poettering! 除非明确指定挂载其他的文件系统到/tmp 在 /etc/fstab中配置， systemd将会挂载/tmp 作为tmpfs。 这意味着它在每次启动时被清空，其大小将被限制在系统的RAM（内存）大小的50％。 要知道这是为什么，以及想要的行为和如何对其进行修改，请参考：API File Systems。 I FUCKING LOVE LENNART POETTERING! Now this interpretation of how a userspace should look like is implemented and was introduced with big criticism and change in the sense that it fails more quickly. Yao and Shun