Disk concept in linux

 

Managing disks in Linux involves moving from raw hardware to usable storage through a three-layer process: Physical Disks, Partitions, and Filesystems.

1. Basic Disk Concepts
  • Block Devices: Linux treats disks as files. SCSI/SATA drives are usually named /dev/sdX (e.g., /dev/sda)
  • Partitions: Slicing a physical disk into logical sections. This allows you to isolate data (e.g., keeping the OS separate from user files). Common table types are GPT (modern) and MBR (legacy).
  • Filesystems: The method used to store and retrieve data. Common types include ext4 (standard), XFS (high performance), and Btrfs (advanced features).
  • Mount Points: In Linux, you don’t have “C:” or “D:” drives. Instead, you attach a filesystem to a directory (e.g., /mnt/data). This is called “mounting.”

 

2. How to Manage Disks (The Workflow)
To prepare a new disk for use, follow these four standard steps:
  1. Identify the Disk: Use lsblk to see all connected disks and their current structure.
  2. Create Partitions: Use fdisk (for MBR) or gdisk (for GPT) to create a new partition.
    • Example: sudo fdisk /dev/sdb
  3. Format the Partition: Create a filesystem on the partition so it can hold data.
    • Example: sudo mkfs.ext4 /dev/sdb1
  4. Mount the Disk: Connect the filesystem to the directory tree.
    • Example: sudo mount /dev/sdb1 /mnt/new_disk
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