Using Uuids To Mount Devices; Naming Devices With Udev; Understanding Uuids - Novell LINUX ENTERPRISE SERVER 10 SP2 - STORAGE ADMINISTRATION GUIDE 05-15-2009 Administration Manual

Using UUIDs to Mount Devices

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This section describes the optional use of UUIDs instead of device names to identify file system
devices in the boot loader file and the
Section 3.1, "Naming Devices with udev," on page 31
Section 3.2, "Understanding UUIDs," on page 31
Section 3.3, "Using UUIDs in the Boot Loader and /etc/fstab File (x86)," on page 32
Section 3.4, "Using UUIDs in the Boot Loader and /etc/fstab File (IA64)," on page 33
Section 3.5, "Additional Information," on page 34

3.1 Naming Devices with udev

In the Linux 2.6 and later kernel,
with persistent device naming. As part of the hotplug system,
or removed from the system.
A list of rules is used to match against specific device attributes. The
(defined in the
/etc/udev/rules.d
regardless of their order of recognition or the connection used for the device. The
examine every appropriate block device that the kernel creates to apply naming rules based on
certain buses, drive types, or file systems. For information about how to define your own rules for
, see Writing udev Rules
udev
Along with the dynamic kernel-provided device node name,
symbolic links pointing to the device in the
the , ,
by-id by-label by-path
NOTE: Other programs besides
not listed in .
/dev/disk

3.2 Understanding UUIDs

A UUID (Universally Unique Identifier) is a 128-bit number for a file system that is unique on both
the local system and across other systems. It is a randomly generated with system hardware
information and time stamps as part of its seed. UUIDs are commonly used to uniquely tag devices.
Section 3.2.1, "Using UUIDs to Assemble or Activate File System Devices," on page 32
Section 3.2.2, "Finding the UUID for a File System Device," on page 32
file.
/etc/fstab
provides a userspace solution for the dynamic
udev
directory) provides stable names for all disk devices,
(http://reactivated.net/writing_udev_rules.html).
/dev/disk
, and subdirectories.
by-uuid
, such as LVM or
udev
is executed if a device is added
udev
rules infrastructure
udev
maintains classes of persistent
udev
directory, which is further categorized by
, might also generate UUIDs, but they are
md
Using UUIDs to Mount Devices
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directory,
/dev
tools
udev
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