pyrox.dev
1<chapter xmlns="http://docbook.org/ns/docbook"
2 xmlns:xlink="http://www.w3.org/1999/xlink"
3 xmlns:xi="http://www.w3.org/2001/XInclude"
4 version="5.0"
5 xml:id="ch-file-systems">
6
7<title>File Systems</title>
8
9<para>You can define file systems using the
10<option>fileSystems</option> configuration option. For instance, the
11following definition causes NixOS to mount the Ext4 file system on
12device <filename>/dev/disk/by-label/data</filename> onto the mount
13point <filename>/data</filename>:
14
15<programlisting>
16fileSystems."/data" =
17 { device = "/dev/disk/by-label/data";
18 fsType = "ext4";
19 };
20</programlisting>
21
22Mount points are created automatically if they don’t already exist.
23For <option>device</option>, it’s best to use the topology-independent
24device aliases in <filename>/dev/disk/by-label</filename> and
25<filename>/dev/disk/by-uuid</filename>, as these don’t change if the
26topology changes (e.g. if a disk is moved to another IDE
27controller).</para>
28
29<para>You can usually omit the file system type
30(<option>fsType</option>), since <command>mount</command> can usually
31detect the type and load the necessary kernel module automatically.
32However, if the file system is needed at early boot (in the initial
33ramdisk) and is not <literal>ext2</literal>, <literal>ext3</literal>
34or <literal>ext4</literal>, then it’s best to specify
35<option>fsType</option> to ensure that the kernel module is
36available.</para>
37
38<note><para>System startup will fail if any of the filesystems fails to mount,
39dropping you to the emergency shell.
40You can make a mount asynchronous and non-critical by adding
41<literal>options = [ "nofail" ];</literal>.
42</para></note>
43
44<xi:include href="luks-file-systems.xml" />
45
46</chapter>