Mount a Disk in Linux (fstab)

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This guide covers how to find a disk, format it, mount it manually, and make the mount permanent using /etc/fstab on Debian-based Linux systems (Ubuntu, Debian, Pop!_OS).

Step 1 – Find Your Disk

List all connected disks and partitions:

lsblk

Example output:

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0  500G  0 disk
└─sda1   8:1    0  500G  0 part /
sdb      8:16   0    2T  0 disk

Here sdb is the new disk with no partitions yet.

Step 2 – Format the Disk

Formatting erases all data on the disk. Make absolutely sure you have the right disk before proceeding.

Create a new partition table and partition:

sudo fdisk /dev/sdb

Inside fdisk:

Press g to create a new GPT partition table
Press n to create a new partition
Press Enter three times to accept defaults (uses full disk)
Press w to write and exit

Format the partition as ext4:

sudo mkfs.ext4 /dev/sdb1

Step 3 – Create a Mount Point

Create the folder where the disk will be accessible:

sudo mkdir -p /mnt/storage

Step 4 – Mount the Disk Manually

Test the mount before making it permanent:

sudo mount /dev/sdb1 /mnt/storage

Verify it worked:

df -h | grep storage

Step 5 – Make It Permanent with fstab

Find the disk’s UUID (never use /dev/sdb in fstab — device names can change after reboot):

sudo blkid /dev/sdb1

Example output:

/dev/sdb1: UUID="a1b2c3d4-e5f6-7890-abcd-ef1234567890" TYPE="ext4"

Copy the UUID, then open fstab:

sudo nano /etc/fstab

Add this line at the bottom (replace the UUID with yours):

UUID=a1b2c3d4-e5f6-7890-abcd-ef1234567890  /mnt/storage  ext4  defaults  0  2

What the fields mean:

UUID=... — the disk identifier
/mnt/storage — where it mounts
ext4 — filesystem type
defaults — standard mount options
0 — do not dump (backup)
2 — fsck order (2 = check after root disk)

Step 6 – Test the fstab Entry

Test without rebooting:

sudo mount -a

If no errors appear, the fstab entry is correct. The disk will now mount automatically on every boot.

Set Permissions (Optional)

If you want your regular user to write to the disk:

sudo chown -R $USER:$USER /mnt/storage

Quick Reference

Command	What it does
`lsblk`	List all disks and partitions
`sudo blkid /dev/sdb1`	Show UUID of a partition
`sudo fdisk /dev/sdb`	Partition a disk
`sudo mkfs.ext4 /dev/sdb1`	Format as ext4
`sudo mount /dev/sdb1 /mnt/storage`	Mount manually
`sudo mount -a`	Mount all fstab entries
`df -h`	Show mounted disks and usage