Managing Disk Partitions

Partitioning is essential for organizing disk storage in Linux. It allows us to efficiently allocate space for the operating system, swap, data storage, and other purposes. 

Disk Storage and Devices

• Storage devices in Linux are represented by device files:
  • HDD/SSD: /dev/sda, /dev/sdb, etc.
  • Partitions: /dev/sda1, /dev/sda2, etc.
• Storage types in Linux:
  • HDD (Hard Disk Drives): It is a spinning disk part and is slower.
  • SSD (Solid-State Drives): It is faster, with no moving parts, unlike HDD.
  • NVMe (Non-Volatile Memory Express): It is a high-speed SSD and an advanced form of SSD.

Tools/Commands for Disk Management

• fdisk: Partition disks using MBR(Master Boot Record) or GPT(GUID Partition Table).
• parted: Partition disks, especially GPT.
• lsblk: List block devices and their partition layouts.
• blkid: View UUIDs(Universal Unique Identifier) and filesystem types of partitions.

Partition Disk Layout

• A disk can be logically divided into several partitions, each must be formatted with a filesystem (e.g., ext4, xfs, NTFS) as needed.
• The common partition types used are:-
  • Primary Partition: Up to 4 partitions in MBR.
  • Extended Partition: A container for logical partitions (MBR).
  • Logical Partition: Partitions within the extended partition.
  • EFI System Partition (ESP): Required for UEFI(Unified Extensible Firmware Interface) boot (GPT).

MBR and GPT Partitions

MBR (Master Boot Record):

• This is a Legacy partitioning scheme.
• Limitations:
  • This partition supports up to 4 primary partitions.
  • The maximum disk partition size is 2 TB.
  • This stores partition data in a single sector (prone to corruption).

GPT (GUID Partition Table):

• This is a modern partitioning scheme used with UEFI systems.
• Advantages:
  • This partition supports up to 128 partitions (no primary/extended distinction).
  • This partition handles disks larger than 2 TB.
  • This partition has redundant partition tables for reliability.

Creating MBR Partitions

Step1 : Use the fdisk command first as:-

Step2 : Now, Create a new partition using the following:

• • Press n to create a partition.
  • Select the primary or extended partition we want to create.
  • Now, choose the partition number and size as needed.

Step3 : Now, Write changes:

• • Press w to write the partition table.

Creating MBR Extended and Logical Partitions

Step1 : Create an extended partition first :

• • For this, Use fdisk and press n.
  • Select e for an extended partition.

Step2 : Now, add/create logical partitions:

• • Within the extended partition, we create multiple logical partitions by pressing n and selecting logical.

Step3 : Write desired changes:

sudo partprobe  # Inform the kernel of partition changes

Managing GPT Partitions

Step1 : Use parted command

Step2 : Create a new GPT desired disk label

Step3 : Create partitions type and size

Step4 : To verify the partition table

Working with SSD

For 0ptimizing SSD Usage

Step1 : Use the fstrim command to enable TRIM(help the built-in garbage collection)

Step2 : Choose Filesystem

• • Use ext4 or xfs, as they handle SSDs efficiently.

Step3 : Mount options:

• • Add discard or use fstrim command for TRIM support.

Adding a Swap Partition

Steps to Add Swap Partitions:

Step1 : Create a swap partition

• • • Use fdisk or parted command to create a new partition.
    • Set the partition type to swap (code 82 in MBR).

Step2 : Format the created partition

Step3 : Enable/Active the swap partition

Step4 : Make it persistent

• • • Add it to /etc/fstab
      /dev/sdX2 none swap sw 0 0

Encrypted Partitions

• Encryption ensures that unauthorized users cannot access data stored on a disk.
• A common encryption tool is LUKS (Linux Unified Key Setup), an industry-standard disk encryption.

Configuring Encrypted Partitions

Steps to Encrypt a Partition Using LUKS:

Step1 : Install cryptsetup

Step2 : Initialize the partition for encryption

Step3 : Open the encrypted partition

Step4 : Format the partition

Step5 : Mount the encrypted partition

Step6 : Make it persistent

Add an entry in /etc/crypttab

Update /etc/fstab:

Summary of Commands Used in Managing Disk Partitions