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UUID (Universal Unique Identifier)
notation is another way provided by
Linux to access your disks. Unlike the standard /dev/hda1
notation, it is linked specifically to a particular piece
of hardware (whereas /dev/
notation can shift between disks depending
on how they're plugged in). This means you don't have the risk of a
system reconfiguration causing disks to be renamed, and thus causing
knock-on breakage of things that reference that disk.
OK, so, first, how do you find out the UUID of your disk? The command
blkid can be used here's its output for one of my disks:
# blkid /dev/hda1
/dev/hda1: UUID="0ef96300-36c0-4575-8a1d-2d36ff4cd585" SEC_TYPE="ext2" TYPE="ext3"
Alternatively, you can look at the /dev/disk/by_uuid/
see which UUID is associated with which disk. (Use df
to find out
what device names you currently have mounted.)
You can also do this the other way around, starting from the UUID:
will tell you which disk is associated with that
Once you have the UUID of a device, you can use it with mount by
using the -U switch:
mount -U 0ef96300-36c0-4575-8a1d-2d36ff4cd585 /mnt/disk1
or, you can use it in your /etc/fstab
by putting UUID=uuid
the start of the relevant line, instead of /dev/hdaX
To assign a UUID to a disk, use tunefs. You can generate your own
UUID with the command uuidgen. Then type:
tune2fs -U uuid /dev/sda2
This might come in handy if, say, you've cloned your disk (e.g., by using
) and must be able to mount both the original and the clone.
Assign it a new UUID and you're away!
This article was first published on ServerWatch.com.