Finding the UUID for Linux Drives

The Universally Unique Identifier (UUID) is a good way to mount drives under Linux with SATA drives (or any drives, PATA or IDE).  This ensures that when you have more than one harddrive, it always gets mounted to the same location specified in /etc/fstab.  The reason is that SATA drives are mounted when they're found and on one reboot can come up as /dev/sda and the next time as /dev/sdb.

So in order to set up your file system table correctly, you should specify the UUID instead of the physcial device.  So you're /etc/fstab will look like this:

# /dev/sda3
UUID=d0082790-10b3-466a-8408-a109a6d1a010 /               ext3    relatime,errors=remount-ro 0       1
# /dev/sda1
UUID=213d26d6-3fe8-4443-a50d-9d1fea138ac5 /boot           ext3    relatime        0       2
# /dev/sda6
UUID=485554c3-e681-4254-9344-6f038c826fb8 /home           ext3    relatime        0       2
# /dev/sda5
UUID=f95f1c10-8496-481c-a84b-e8f8a4ec9061 /var            ext3    relatime        0       2
# /dev/sda2
UUID=82b38f49-9f85-4d32-887b-24357b0661c8 none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto,exec,utf8 0       0
/dev/sdb1       /media/sdb1                               ext3    relatime        0       0

Ok, so if you want to use the UUID, how can you find it?  We're assuming the drive is already mounted, of course!

One way is to use

$ ls -l /dev/disk/by-uuid
lrwxrwxrwx 1 root root 10 11. Okt 18:02 485554c3-e681-4254-9344-6f038c826fb8 -> ../../sda2

This will list all the devices by UUID and tell you where they're currently mounted.  Another would be to use the blkid command.

# blkid /dev/sda1
/dev/sda1: LABEL="/" UUID="485554c3-e681-4254-9344-6f038c826fb8" SEC_TYPE="ext2" TYPE="ext3"

One problem with this is that the blkid command can only list one device at a time.  A secondary problem is that the command blkid has to be run as the root user.

Additional information can be found by googling Linux and UUID.