my-docs/Linux/Basic Administration/25-disk-manage.md

📘 Disk Partitioning Guide: MBR & GPT using fdisk and gdisk

🔹 Overview

• Use **fdisk** for MBR (Master Boot Record) partitioning.
• For GPT (GUID Partition Table), the recommended tool is **gdisk**, but fdisk also supports GPT.

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🧰 Disk Partitioning with fdisk

🔍 List Partitions

Command	Description
fdisk -l	Show list of available partitions
fdisk -x	Show list with extended information

⚙️ Launch fdisk

fdisk /dev/sdX

Replace /dev/sdX with your actual disk name (e.g., /dev/sdb).

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📖 Inside fdisk

Once inside the fdisk prompt:

Key	Function
m	Show help
p	Print partition table (disk info)
n	Create new partition
t	Change partition type
w	Write changes and exit

➕ Creating a Partition (n)

• Choose p for primary or e for extended partition.
• MBR allows 4 primary partitions. One of them can be extended, which can hold logical partitions.

📏 Define Partition Size

Example:

+512M

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🧱 Create Filesystem

To format the partition with ext4:

mkfs.ext4 /dev/sdb1

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🔗 Get Partition UUID

Option 1: After formatting, the UUID is shown in output. Option 2: Use blkid to retrieve it:

blkid

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📝 Mount Using /etc/fstab

1. Open the fstab configuration file:

vim /etc/fstab

2. Add the following line:

/dev/disk/by-uuid/<UUID> <mount_path> <filesystem> defaults 0 1

Example:

/dev/disk/by-uuid/1eb043d2-f2ee-4a69-a7c4-13c283c3ccc6 /test ext4 defaults 0 1

This ensures the partition is mounted automatically at boot.

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✅ Summary

Task	Command/Action
List partitions	fdisk -l
Start partitioning	fdisk /dev/sdX
Format partition	mkfs.ext4 /dev/sdX1
Get UUID	blkid
Edit fstab	vim /etc/fstab