Linux Administrator

How to Change Partition UUID in Linux

The UUID of a Linux partition is the Universally Unique IDentifier of that partition. I would say with a fair bit of confidence that in this and most scenarios, the Linux partition UUID has more of a local machine scope. This ID is used in a few places to identify the partition. The most notable being your /etc/fstab file, which manages the mounting of partitions at boot time.

UUID should be unique and it is used to identify storage devices on a Linux system.

In this article I will show how to change UUID of Linux partition.

Change UUID of Linux Partition

Follow the below steps to change the UUID of Linux Partition.

1. Run the below command to find out UUID of the devices.

# blkid

/dev/mapper/centos_centos71-root: UUID="2bc8e0d4-64b5-4dc8-bf4a-024fc980d98a" TYPE="ext4"
/dev/mapper/centos_centos71-swap: UUID="577f9541-8d2a-4666-ac8f-ff84b584eeca" TYPE="swap"
/dev/mapper/vg_data-centos7_vol: UUID="b100ad2b-ad89-4e2d-ba8e-7eda7d703c40" TYPE="ext4"

2. Alternatively you can also use the below command to find out the UUID of devices.

# ls -l /dev/disk/by-uuid
total 0
lrwxrwxrwx 1 root root 10 Dec 20 23:16 2bc8e0d4-64b5-4dc8-bf4a-024fc980d98a -> ../../dm-1
lrwxrwxrwx 1 root root 10 Dec 20 23:16 577f9541-8d2a-4666-ac8f-ff84b584eeca -> ../../dm-0
lrwxrwxrwx 1 root root 10 Dec 20 23:19 b100ad2b-ad89-4e2d-ba8e-7eda7d703c40 -> ../../dm-2

3. Check the mounted partitions.

# df -lh
Filesystem                        Size  Used Avail Use% Mounted on
/dev/mapper/centos_centos71-root   24G  3.1G   19G  15% /
devtmpfs                          1.9G     0  1.9G   0% /dev
tmpfs                             1.9G     0  1.9G   0% /dev/shm
tmpfs                             1.9G   25M  1.9G   2% /run
tmpfs                             1.9G     0  1.9G   0% /sys/fs/cgroup
tmpfs                             500M     0  500M   0% /etc/nginx/cache
/dev/sda1                         477M  230M  218M  52% /boot
tmpfs                             380M     0  380M   0% /run/user/0
/dev/mapper/vg_data-centos7_vol   9.8G   37M  9.2G   1% /data

There is mounted /data in the system with UUID=”b100ad2b-ad89-4e2d-ba8e-7eda7d703c40″.

4. Change UUID for /dev/mapper/vg_data-centos7_vol which is in /data mounted partition.

  • 1.Create the new UUID using below command.
# uuidgen
fb5c697b-d1d6-49ab-afcd-27a22a5007c8
  • 2. Please take note that the UUID may only be changed when the filesystem is unmounted.
# umount /data
  • 3. Now change UUID for LVM /dev/mapper/vg_data-centos7_vol with new generated UUID.
# tune2fs /dev/mapper/vg_data-centos7_vol -U fb5c697b-d1d6-49ab-afcd-27a22a5007c8
tune2fs 1.42.9 (28-Dec-2013)
  • 4. Mount back the /data partition.
# mount /dev/mapper/vg_data-centos7_vol /data
  • 5. Update /etc/fstab.
UUID=fb5c697b-d1d6-49ab-afcd-27a22a5007c8 /data                   ext4    defaults        1 2
  • 6. Verify new UUID for /dev/mapper/vg_data-centos7_vol.
# blkid

/dev/mapper/centos_centos71-root: UUID="2bc8e0d4-64b5-4dc8-bf4a-024fc980d98a" TYPE="ext4"
/dev/mapper/centos_centos71-swap: UUID="577f9541-8d2a-4666-ac8f-ff84b584eeca" TYPE="swap"
/dev/mapper/vg_data-centos7_vol: UUID="fb5c697b-d1d6-49ab-afcd-27a22a5007c8" TYPE="ext4"
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Santosh Prasad

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