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