List, create, and delete partitions on GPT disks

5.1 List, create, and delete partitions on GPT disks

📘Red Hat Certified System Administrator (RHCSA – EX200)

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In IT systems, storage is divided into disks and partitions. A GPT disk (GUID Partition Table) is a modern way to organize data on a hard drive or SSD, especially for disks larger than 2 TB. GPT is part of the UEFI standard and is replacing the older MBR (Master Boot Record) system.

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1. Understanding GPT Disks

• GPT (GUID Partition Table) uses globally unique identifiers (GUIDs) to identify partitions.
• A GPT disk can have up to 128 partitions by default, without needing “extended” or “logical” partitions like MBR.
• GPT stores backup partition tables at the start and end of the disk for recovery.
• Each partition has a unique GUID and can store a specific type of data (e.g., Linux filesystem, swap, EFI system partition).

Key Points for Exam:

• Recognize the difference between GPT vs MBR.
• Know that GPT is required for UEFI boot.
• You should know how to list, create, and delete partitions using Linux command-line tools.

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2. Listing Partitions on GPT Disks

Before creating or deleting partitions, you must know what’s on the disk.

Common commands:

1. lsblk – Lists block devices and partitions in a tree format:

lsblk

• Shows disks (/dev/sda, /dev/sdb) and their partitions (/dev/sda1, /dev/sda2).

2. parted – A tool for GPT and MBR disks:

sudo parted /dev/sda print

• Displays:
  • Disk size
  • Partition numbers
  • File system type
  • Flags (like bootable)
  • Partition start and end points

3. gdisk – GPT-specific tool:

sudo gdisk -l /dev/sda

• Shows partition table with GUIDs and type codes.

Tip for exam: Always check the disk you want to modify to avoid deleting important data.

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3. Creating Partitions on GPT Disks

To create a new partition:

Using parted

1. Start parted on your disk:

sudo parted /dev/sda

2. Create a new partition table (if needed):

mklabel gpt

• gpt tells the system to use the GPT partition table format.

3. Create a new partition:

mkpart primary ext4 1MiB 10GiB

• primary – Partition type (GPT doesn’t need extended/logical distinction)
• ext4 – File system type (can also use xfs, swap, etc.)
• 1MiB – Start of partition
• 10GiB – End of partition

4. Exit parted:

quit

Using gdisk

1. Start gdisk on the disk:

sudo gdisk /dev/sda

2. Press:

• n → New partition
• Enter partition number (or press Enter for default)
• Enter start and end sectors (or press Enter for defaults)
• Choose partition type code (e.g., 8300 for Linux filesystem)

3. Write changes:

w

• This saves the new partition to the disk.

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4. Deleting Partitions on GPT Disks

Using parted

sudo parted /dev/sda
rm 1
quit

• rm 1 removes partition number 1.

Using gdisk

1. Start gdisk:

sudo gdisk /dev/sda

2. Press d → select partition number → press Enter
3. Press w → write changes

Important: Deleting a partition removes all data in it. Always double-check which partition you’re deleting.

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5. Exam Tips for DEVASC

1. Know commands: lsblk, parted, gdisk.
2. Know GPT vs MBR: GPT allows more partitions and uses GUIDs.
3. Understand partition types: Linux filesystems, swap, EFI system.
4. Start and end points: You can define exact sizes in MiB/GiB.
5. Practical: Be able to list, create, and delete partitions in a Linux environment.

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✅ Summary Table

Task	Command Example	Notes
List partitions	lsblk / sudo parted /dev/sda print	Shows existing partitions and sizes
Create GPT table	sudo parted /dev/sda mklabel gpt	Only if disk is empty or you want to reformat
Create partition	sudo parted /dev/sda mkpart primary ext4 1MiB 10GiB	Creates a new ext4 partition
Delete partition	sudo parted /dev/sda rm 1	Deletes partition 1 (careful!)
GPT-specific creation	sudo gdisk /dev/sda → n → w	Alternative tool, handles GUIDs

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This knowledge ensures you can handle any GPT disk partition task on a Linux system for the DEVASC exam.