How to Mount Disk on Linux Server

Step 1: Check Disk Information

Before mounting, first check if your server detects the new disk.
Run:

lsblk

This will list all disks.

Typically, you will see something like sda (system disk) and sdb (new disk to mount). This step works on Ubuntu, Debian, CentOS, and almost all Linux distributions.

Step 2: Format the Disk

To use the new disk, you must format it with a file system.
For ext4:

mkfs -t ext4 /dev/sdb

For xfs:

mkfs.xfs /dev/sdb

Tip: If you want to mount external disk Linux (like USB HDD/SSD), formatting may erase data. Make sure to back up important files.

Step 3: Mount the Disk Temporarily

Create a directory where you want to mount the disk:

mkdir /second

Then mount it:

mount /dev/sdb /second

Now your disk is accessible at /second.

Step 4: Mount the Disk Permanently

By default, temporary mounts are lost after reboot. To make the mount permanent:
Open the fstab file:

vi /etc/fstab

Add one of the following lines depending on the file system:
For ext4:

/dev/sdb  /second ext4 defaults 0 0

For xfs:

/dev/sdb  /second xfs defaults 0 0

Save and exit.

From now on, Linux will mount disk automatically at boot.

Step 5: Verify Disk Mount

To confirm the disk is mounted:

df -TH

You should see /dev/sdb listed under /second.

This confirms your new disk (HDD, SSD, NVMe, or external) is mounted correctly.