Always Mount Drives Reliably with UUIDs or Labels.

If your USB drive or disk partition keeps changing from /dev/sdc2 to /dev/sdd2 (or another device name), this guide explains why it happens and how to fix it properly.

Why /dev/sdX Keeps Changing

Linux assigns device names dynamically.
Relying on /dev/sdX is therefore unreliable.

Common causes include:

• Dynamic device enumeration
  During boot, Linux scans drives and assigns letters based on detection order. Adding or removing drives can change the assignment.
• Hotplugging USB devices
  Unplugging and re-plugging a USB drive may assign it a new device node.
• Multiple controllers or card readers
  Different USB ports or hub configurations can cause the same drive to appear under a different name.

⚠️ Warning: Using /dev/sdX in scripts, automounts, or rules can lead to broken mounts.

Use Persistent Identifiers

Instead of /dev/sdX, use:

• UUID (Universally Unique Identifier): Unique per filesystem.
• LABEL: A human-readable name assigned to the filesystem (optional).

These identifiers are stable and do not change, regardless of which /dev/sdX is assigned.

Find the UUID or Label

Using lsblk

$ lsblk -f

Example output:

NAME   FSTYPE LABEL  UUID                                 MOUNTPOINT
sdc2   ext4   DATA   a1b2c3d4-5678-90ef-1234-567890abcdef

• UUID: a1b2c3d4-5678-90ef-1234-567890abcdef
• Label: DATA (optional)

Using blkid

$ sudo blkid /dev/sdc2

Example output:

/dev/sdc2: UUID="a1b2c3d4-5678-90ef-1234-567890abcdef" TYPE="ext4" PARTUUID="12345678-02"

Create the Mount Point

Before mounting, create the directory where the drive will be attached:

$ sudo mkdir -p /mnt/data

• Replace /mnt/data with any directory you prefer.
• Ensure the directory is empty; otherwise, files already in it may become inaccessible while the drive is mounted.

Edit /etc/fstab for Stable Automount

Instead of using /dev/sdX, use the UUID:

UUID=a1b2c3d4-5678-90ef-1234-567890abcdef  /mnt/data  ext4  defaults  0 2

Optional: Mount by label:

LABEL=DATA  /mnt/data  ext4  defaults  0 2

Notes:

• defaults uses standard mount options.
• 0 2 sets the filesystem check order at boot (usually fine for most drives).

Test the Mount

After editing /etc/fstab, test it:

$ sudo mount -a

• No output means success.

Verify the mount:

$ df -h | grep /mnt/data

If you see the drive mounted, everything is working as expected.

Extra Tips

• Label your drives for easier identification:

$ sudo e2label /dev/sdc2 DATA   # For ext4
$ sudo dosfslabel /dev/sdc1 MYUSB # For FAT32

• Avoid /dev/sdX in scripts — always use UUID or LABEL.
• For hotplugged drives, consider using udev rules or systemd automount.
• Check active mounts with:

findmnt
df -h

Always use UUID or LABEL instead of /dev/sdX for stable, persistent mounts. Properly configuring /etc/fstab and labeling drives prevents broken mounts, ensures consistent access, and keeps scripts and automounts reliable.