6.2 About the Udev Device Manager

The udev device manager dynamically creates or removes device node files at boot time or if you add a device to or remove a device from the system with a 2.6 version kernel or later. When creating a device node, udev reads the device’s /sys directory for attributes such as the label, serial number, and bus device number.

Udev can use persistent device names to guarantee consistent naming of devices across reboots, regardless of their order of discovery. Persistent device names are especially important when using external storage devices.

The configuration file for udev is /etc/udev/udev.conf, in which you can define the following variables:


The logging priority, which can be set to err, info and debug. The default value is err.


Specifies the location of the device nodes. The default value is /dev.

For more information, see the udev(7) manual page.