Creating a Unique Disk Identifier with fdisk

{code}
Can not back up /dev/sdb partition since /dev/sda partition has the same identifier.

{kb-resolution}
A unique disk identifier must be created.
{note:title=Warning}This is a dangerous operation. Make sure all data has been backed up *before* changing any partition information on your disk. A failure in changing partition data can make the machine unbootable.
{note}
{info:title=Note}Some operating systems such as RHEL 5 and Centos use an older version of fdisk contained in the util-linux package, which does not include the ability to change the disk identifier. The util-linux package has been replaced in more updated operating systems with the util-linux-ng package. In these cases you would need to manually upgrade the fdisk utility.
{info}
{code}
# fdisk /dev/<device>
fdisk> x (for advanced)
fdisk> i (to change the disk identifier)
# Enter in an arbitrary number.
{code}
{kb-related-articles}