Partitions — Organizing Storage Devices in Linux¶

A partition is a logical division of a physical storage device that allows a single disk to be divided into multiple independent sections. Each partition can contain its own filesystem, operating system, application data, or swap space. Proper partitioning improves organization, security, performance, and storage management. Understanding partitions is an essential skill for Linux administrators, DevOps engineers, Cloud Architects, Platform Engineers, and Site Reliability Engineers (SREs).

Learning Path¶

Linux Mastery → Module 9: Storage Management → Lesson 1

Difficulty: Beginner → Intermediate

Reading Time: 75 Minutes

Course Progress

Course: Linux Mastery

Module: Storage Management

Lesson: 1 of 10

What You'll Learn¶

After completing this lesson, you'll be able to:

Understand disk partitions
Learn partition table types
View existing partitions
Create and delete partitions
Understand primary, extended, and logical partitions
Work with GPT and MBR
Prepare disks for filesystems
Apply partitioning best practices in production

Prerequisites¶

Complete:

Module 1 – Linux Fundamentals
Module 2 – Linux Command Line Essentials
Module 3 – Text Processing
Module 4 – File Management
Module 5 – Users and Groups
Module 6 – Process Management
Module 7 – Package Management
Module 8 – Networking

Why Learn Partitions?¶

Imagine:

Installing Linux on a new server.
Adding a new SSD to a cloud virtual machine.
Creating separate storage for databases.
Isolating application logs from the operating system.
Preparing disks before configuring LVM or RAID.

The first step in all these scenarios is partitioning the storage device.

What is a Partition?¶

A partition is a logical section of a physical storage device.

Example:

Physical Disk

/dev/sda
│
├── /dev/sda1
├── /dev/sda2
└── /dev/sda3

Each partition behaves like an independent storage device.

It can contain:

A filesystem
Swap space
LVM Physical Volume
Database storage
Application data

Why Use Partitions?¶

Partitions help:

Separate operating system files from user data
Improve storage organization
Simplify backups
Improve security
Reduce the impact of filesystem corruption
Prepare storage for enterprise workloads

Example:

Disk

├── /
├── /boot
├── /home
├── /var
└── swap

Each partition serves a different purpose.

Partition Tables¶

A partition table describes how partitions are organized on a disk.

Linux primarily supports:

MBR (Master Boot Record)
GPT (GUID Partition Table)

MBR (Master Boot Record)¶

Characteristics:

Supports disks up to 2 TB
Maximum 4 primary partitions
Used by legacy BIOS systems

Example:

Disk

├── Primary
├── Primary
├── Primary
└── Primary

Limitations:

Maximum disk size of 2 TB
Limited number of partitions

Extended and Logical Partitions¶

Because MBR supports only four primary partitions, one primary partition can be converted into an Extended Partition.

Example:

Primary

Primary

Primary

Extended
        │
        ├── Logical
        ├── Logical
        ├── Logical
        └── Logical

Logical partitions exist only inside the extended partition.

GPT (GUID Partition Table)¶

GPT is the modern partitioning standard.

Advantages:

Supports disks larger than 2 TB
Typically supports 128 partitions
Better reliability
Redundant partition table
Required for UEFI boot systems

GPT is recommended for almost all modern Linux installations.

Device Naming¶

Linux names storage devices as follows:

SATA/SCSI disks:

/dev/sda

/dev/sdb

NVMe disks:

/dev/nvme0n1

Partitions:

/dev/sda1

/dev/sda2

/dev/nvme0n1p1

View Available Disks¶

Display storage devices.

lsblk

Example:

NAME

sda

├── sda1

├── sda2

└── sda3

View Partition Details¶

sudo fdisk -l

Displays:

Disk size
Partition table type
Partition sizes
Bootable partitions

View Filesystem Information¶

blkid

Example:

UUID

TYPE

LABEL

View Partition Table¶

Using parted:

sudo parted /dev/sda print

Shows:

Partition table type
Partition layout
Start/end sectors
Partition sizes

Create a Partition Using fdisk¶

Open the disk.

sudo fdisk /dev/sdb

Common interactive commands:

Create a new partition.

Primary partition (MBR only).

Write changes to disk.

Create a GPT Partition Using parted¶

Start parted.

sudo parted /dev/sdb

Create GPT.

mklabel gpt

Create partition.

mkpart primary ext4 1MiB 20GiB

Exit.

quit

Reload Partition Table¶

Inform the kernel about partition changes.

sudo partprobe

If necessary, reboot the system.

Delete a Partition¶

Using fdisk:

Delete selected partition.

Save changes.

Warning: Deleting a partition removes it from the partition table. The filesystem becomes inaccessible and data recovery may not be possible without specialized tools.

Common Commands¶

Display disks.

lsblk

Display partitions.

sudo fdisk -l

Show UUIDs.

blkid

Partition management.

sudo fdisk /dev/sdb

Modern partition management.

sudo parted /dev/sdb

Reload partition table.

sudo partprobe

Real Production Examples¶

Inspect a new cloud volume.

lsblk

View partition details.

sudo fdisk -l

Create a GPT partition.

sudo parted /dev/nvme0n1

Reload partition table.

sudo partprobe

Production Perspective¶

Partitions are commonly used for:

Linux installations
Database storage
Application data
Log storage
Backup volumes
Cloud virtual machines
LVM Physical Volumes
RAID configurations

Proper partition planning makes storage easier to manage and expand.

Hands-on Lab¶

Task 1¶

Display storage devices.

lsblk

Task 2¶

View partition information.

sudo fdisk -l

Task 3¶

Display UUIDs.

blkid

Task 4¶

Display the partition table.

sudo parted /dev/sda print

Task 5¶

Create a partition on a test disk.

sudo fdisk /dev/sdb

Never perform this exercise on a production disk.

Task 6¶

Reload the partition table.

sudo partprobe

Task 7¶

Verify the new partition.

lsblk

Task 8¶

Review the updated partition layout.

sudo fdisk -l

Command Deep Dive¶

Command	Purpose	Production Example
`lsblk`	View disks and partitions	Storage inventory
`fdisk -l`	Display partition information	Capacity planning
`blkid`	View filesystem UUIDs	Mount configuration
`fdisk`	Create or modify partitions	Disk preparation
`parted`	GPT partition management	Enterprise storage
`partprobe`	Reload partition table	Apply changes

MBR vs GPT¶

Feature	MBR	GPT
Maximum Disk Size	2 TB	Greater than 2 TB
Maximum Partitions	4 Primary	Typically 128
UEFI Support	No	Yes
Redundant Metadata	No	Yes
Recommended Today	Legacy Systems	Modern Systems

Production Troubleshooting Scenario¶

Scenario

A new 8 TB storage volume is attached to a Linux server.

Running:

sudo fdisk -l

shows the disk, but only 2 TB is usable.

Investigation reveals that the disk uses an MBR partition table.

Solution:

Create a GPT partition table.

sudo parted /dev/sdb

mklabel gpt

Create a partition.

mkpart primary ext4 1MiB 100%

Reload the partition table.

sudo partprobe

The full disk capacity is now available.

Best Practices¶

Use GPT for modern Linux systems.
Separate operating system and application data when appropriate.
Verify the target disk before modifying partitions.
Back up important data before changing partition layouts.
Use UUIDs when mounting filesystems.
Leave room for future storage expansion.

Common Mistakes¶

❌ Partitioning the wrong disk.

✅ Avoid this mistake: partitioning the wrong disk.

❌ Using MBR on disks larger than 2 TB.

✅ Avoid using MBR on disks larger than 2 TB when a safer approach exists.

❌ Forgetting to reload the partition table.

✅ Remember to to reload the partition table.

❌ Modifying production disks without backups.

✅ Avoid this mistake: modifying production disks without backups.

❌ Poor partition planning leading to storage shortages.

✅ Avoid this mistake: poor partition planning leading to storage shortages.

Interview Questions¶

Beginner¶

What is a partition?
What is the purpose of a partition table?
What is the difference between MBR and GPT?
Which command lists disk partitions?

Intermediate¶

Why is GPT preferred over MBR?
What is the purpose of partprobe?
How do you create a partition using fdisk?
What are logical partitions?

Architect Level¶

How would you partition storage for a production database server?
How would you migrate from MBR to GPT?
How would you design partition layouts for enterprise Linux servers?

Summary¶

In this lesson, you learned:

Disk partitions
Partition tables
MBR and GPT
Primary, extended, and logical partitions
Partition management tools
Creating and deleting partitions
Production storage best practices

Partitions divide physical storage into logical sections, allowing Linux systems to organize data efficiently, improve reliability, and simplify storage management. Understanding partitioning is the foundation for working with filesystems, LVM, RAID, and enterprise storage solutions.

Key Takeaways¶

Partitions divide physical disks into logical storage areas.
GPT is the recommended partition table for modern Linux systems.
lsblk, fdisk, and parted are essential partition management tools.
Always verify the correct disk before making changes.
Reload the partition table after modifications using partprobe.
Proper partition planning simplifies future storage management.

What's Next?¶

Filesystems — Organizing and Managing Data on Linux Storage

You'll explore:

What a filesystem is
Common Linux filesystem types
Creating filesystems
Formatting partitions
Filesystem labels and UUIDs
Choosing the right filesystem
Production best practices

Understanding filesystems is the next step toward managing Linux storage efficiently.