Disk partitioning means dividing a physical storage device (HDD/SSD) into logical sections called partitions.
These partitions are used to install OS, store files, or create special-purpose areas like swap.

Linux offers tools like fdisk (for MBR disks) and gdisk (for GPT disks) to manage partitions.

1. Partition Tables: MBR vs GPT

MBR (Master Boot Record)

• Older standard

• Supports up to 4 primary partitions

• Supports partitions up to 2 TB

• Used by BIOS systems

GPT (GUID Partition Table)

• Modern standard

• Supports 128+ partitions

• Supports disks larger than 2 TB

• Stores multiple backup metadata (more reliable)

• Used in UEFI systems

2. fdisk — For MBR (and can handle GPT too)

fdisk is a command-line tool used to create and manage partitions.

List all disks using fdisk

sudo fdisk -l

Open a disk for editing

sudo fdisk /dev/sda

Once inside, you’ll use interactive commands:

Common fdisk Commands

Example: Create a new partition using fdisk

1. Open fdisk:

   sudo fdisk /dev/sda
   

2. Press n → new partition

3. Select primary

4. Choose partition number

5. Accept default start sector

6. Set size (example: +20G)

7. Press w to save

After creating partition, you must format it:

sudo mkfs.ext4 /dev/sda3

3. gdisk — For GPT Partitioning

gdisk works like fdisk but is specifically designed for GPT disks.
It is often referred to as the "GPT fdisk".

Start gdisk

sudo gdisk /dev/sda

Common gdisk Commands

Example Partition Type Codes

4. After Partitioning — Format the Partition

Depending on usage:

For Linux filesystem

sudo mkfs.ext4 /dev/sda2

For swap area

sudo mkswap /dev/sda3
sudo swapon /dev/sda3

For FAT32 (USB drives)

sudo mkfs.vfat /dev/sdb1

5. Mounting the Partition

Once formatted:

sudo mkdir /mnt/data
sudo mount /dev/sda2 /mnt/data

To make it persistent, add to /etc/fstab.

6. Checking Partitions

Using lsblk:

lsblk

Using parted:

sudo parted -l

In Summary