How to change disk or partition UUID in Linux

Changing the UUID of a disk or partition prevents conflicts when disks are cloned, swapped between machines, or attached alongside similar layouts. A unique identifier also keeps mount points stable when device names such as sda1 or sdb1 change after hardware modifications.

On Linux systems, mount configuration usually refers to partitions by UUID in /etc/fstab instead of by device name. The kernel and systemd read these identifiers during boot, match them to block devices, and mount filesystems at their configured locations.

Changing a filesystem identifier affects any configuration that refers to the old value, especially entries in /etc/fstab and bootloaders that rely on specific UUIDs. The procedure requires unmounting the filesystem, validating its integrity, assigning the new UUID, and updating configuration files to avoid unmountable filesystems or failed boots.

Steps to change disk or partition UUID in Linux:

Open a terminal with sudo privileges.
```
$ whoami
root
```

List block devices and locate the target partition by name, filesystem type, and existing UUID.

$ lsblk -f
NAME   FSTYPE FSVER LABEL     UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
loop0  ext4   1.0   data      12fc1902-80ea-4b6b-bb14-f0f0df4d994b  906.2M     0% /mnt/data
loop1  ext4   1.0   mountdemo 44518380-11db-4f05-8785-f92c04283278                
loop2  ext4   1.0   uuiddemo  d2b28f4c-5458-4117-9f27-76a8158a35df                
nbd0                                                                              
nbd1                                                                              
nbd2                                                                              
nbd3                                                                              
nbd4                                                                              
nbd5                                                                              
nbd6                                                                              
nbd7                                                                              
vda                                                                               
`-vda1 ext4   1.0             0f29d829-7b21-4784-8807-a473ed0d4528    1.7T     1% /etc/hosts
                                                                                  /etc/hostname
                                                                                  /etc/resolv.conf
vdb    erofs                  ab937823-7fcd-4a20-bf31-2ddb0fb68612                
nbd8                                                                              
nbd9                                                                              
nbd10                                                                             
nbd11                                                                             
nbd12                                                                             
nbd13                                                                             
nbd14                                                                             
nbd15

lsblk with the -f option shows filesystem type, label, and UUID for each partition.

Generate a new UUID value for the filesystem.
```
$ uuidgen
3d3133d9-8a20-4903-b2ed-05a72b7ecb9a
```
uuidgen is normally installed by default on most Linux systems.
Another random UUID can be read from /proc/sys/kernel/random/uuid.
```
$ cat /proc/sys/kernel/random/uuid
cc981e52-711d-4a74-8915-9eee31b45840
```
Unmount the filesystem on the target partition so it can be modified safely.
```
$ sudo umount /dev/loop2
```
Replace loop2 with the actual partition identifier discovered in the listing step.

Check the filesystem for errors before changing the UUID.

$ sudo e2fsck -f /dev/loop2
e2fsck 1.47.0 (5-Feb-2023)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
uuiddemo: 11/65536 files (0.0% non-contiguous), 8268/65536 blocks

This step ensures the filesystem is consistent before applying a new UUID.

Assign the new UUID value to the ext* filesystem with tune2fs.
```
$ sudo tune2fs -U 3d3133d9-8a20-4903-b2ed-05a72b7ecb9a /dev/loop2
tune2fs 1.47.0 (5-Feb-2023)
```
tune2fs operates only on ext2, ext3, and ext4 filesystems; other types such as XFS or Btrfs require tools like xfs_admin or btrfs filesystem label for equivalent operations.

Confirm that the partition now reports the new UUID.

$ sudo blkid /dev/loop2
/dev/loop2: LABEL="uuiddemo" UUID="3d3133d9-8a20-4903-b2ed-05a72b7ecb9a" BLOCK_SIZE="4096" TYPE="ext4"

Update the matching entry in /etc/fstab so that it references the new UUID for the partition.
```
$ sudoedit /etc/fstab
```
```
/etc/fstab
UUID=3d3133d9-8a20-4903-b2ed-05a72b7ecb9a /mnt/uuiddemo ext4 defaults 0 2
##### snipped #####
```
Incorrect /etc/fstab entries can prevent the system from booting if they affect root or other essential filesystems.
Reload fstab-controlled mounts to apply the updated configuration.
```
$ sudo mount -a
```
No output typically indicates that all mounts defined in /etc/fstab succeeded.

Verify that the partition is mounted as expected with the new UUID.

$ findmnt /dev/loop2
TARGET    SOURCE    FSTYPE OPTIONS
/mnt/uuiddemo /dev/loop2 ext4   rw,relatime

Author: Mohd Shakir Zakaria
Mohd Shakir Zakaria is a cloud architect with deep roots in software development and open-source advocacy. Certified in AWS, Red Hat, VMware, ITIL, and Linux, he specializes in designing and managing robust cloud and on-premises infrastructures.

Discuss the article:

Comment anonymously. Login not required.