filesystem.rst 1.3 KB

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  1. :title: File Systems
  2. :description: How Linux organizes its persistent storage
  3. :keywords: containers, files, linux
  4. .. _filesystem_def:
  5. File System
  6. ===========
  7. .. image:: images/docker-filesystems-generic.png
  8. In order for a Linux system to run, it typically needs two `file
  9. systems <http://en.wikipedia.org/wiki/Filesystem>`_:
  10. 1. boot file system (bootfs)
  11. 2. root file system (rootfs)
  12. The **boot file system** contains the bootloader and the kernel. The
  13. user never makes any changes to the boot file system. In fact, soon
  14. after the boot process is complete, the entire kernel is in memory,
  15. and the boot file system is unmounted to free up the RAM associated
  16. with the initrd disk image.
  17. The **root file system** includes the typical directory structure we
  18. associate with Unix-like operating systems: ``/dev, /proc, /bin, /etc,
  19. /lib, /usr,`` and ``/tmp`` plus all the configuration files, binaries
  20. and libraries required to run user applications (like bash, ls, and so
  21. forth).
  22. While there can be important kernel differences between different
  23. Linux distributions, the contents and organization of the root file
  24. system are usually what make your software packages dependent on one
  25. distribution versus another. Docker can help solve this problem by
  26. running multiple distributions at the same time.
  27. .. image:: images/docker-filesystems-multiroot.png