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Disk and Filesystem

Disk and Filesystem
Exploring the Vaults of Storage and the Magic of Persistence

Storage is the foundation of every Linux system. Files, applications, logs, and processes all reside on disks. To master Linux, you must learn how to inspect, organize, and manage storage so that the kingdom’s knowledge remains safe, accessible, and persistent.

Understanding Storage

In Linux (including Ubuntu), storage is managed through block devices, partitions, file systems, and mount points.

Data is organized using file systems like ext4, and devices are mounted into a single unified directory tree starting at /. Tools like LVM, RAID, and NFS extend storage flexibility and scalability

  • Block devices: Physical disks (/dev/sda).
  • Partitions: Logical divisions of a disk (/dev/sda1).
  • Filesystems: Structures like ext4 that organize data.
  • Mount points: Locations in the unified directory tree where devices are attached.
Unlike Windows (C:, D: drives), Linux mounts everything under /. Example: a USB drive may be mounted at /media/usb.
# Component Example Purpose
1 Disk /dev/sda Physical hard drive
2 Partition /dev/sda1 Root partition
3 File system ext4 Organizes files
4 Mount point / Root directory
5 Additional mount /home User data storage

Storage Management Tools

# Tool / Concept Description
1 fdisk/gdisk Partitioning tools.
2 mkfs Create a filesystem on a partition.
3 mount/umount Attach or detach devices.
4 /etc/fstab Configuration file for persistent mounts at boot.
5 LVM Logical Volume Manager for flexible resizing.
6 RAID Combines disks for redundancy or performance.
7 NFS/SMB Network-based storage sharing.

Core Disk Commands

You must learn the commands to explore and manage the dungeon:

# Command Description
1 lsblk Lists block devices (disks and partitions).
2 blkid Shows device identifiers (UUIDs).
3 df -h Displays disk usage in human-readable form.
4 du -sh Shows size of a directory.
5 mount / umount Attaches or detaches a vault.
6 fdisk Creates or modifies partitions.
7 mkfs Creates a filesystem on a partition.

Filesystem Types

You must know the common magical structures:

# Filesystem Description
1 ext4 Default, reliable filesystem for most Linux systems.
2 XFS High-performance, scalable filesystem.
3 Btrfs Advanced features like snapshots and self-healing.
4 FAT32/exFAT Used for USB drives, cross-platform compatibility.
Choice of filesystem affects performance, reliability, and features.

Data Persistence

Mounting a vault manually works, but to ensure persistence across reboots, entries must be added to /etc/fstab.

UUID=1234-5678  /data  ext4  defaults  0  2

# → Ensures the /data vault is mounted automatically at boot.

Why Storage Rocks

# Aspect Description
1 Efficiency Proper partitioning improves performance.
2 Security Separate partitions (like /home, /var) protect against corruption.
3 Flexibility LVM and RAID allow scaling storage without downtime.
4 Integration Unified directory tree makes Linux storage intuitive compared to Windows drive letters.

Practical Exercises

# Add persistence
sudo nano /etc/fstab

# Create a new filesystem
sudo mkfs.ext4 /dev/sdb1

# Mount a vault
sudo mount /dev/sdb1 /mnt

# Check disk usage
df -h
du -sh /home/apprentice

# Explore block devices
lsblk

Hackers Quest

Create a Vault of Knowledge:

  • Partition a disk (or virtual disk)
  • Format it with ext4
  • Mount it at /vault
  • Store files inside
  • Configure /etc/fstab for persistence
  • Document the process in your spellbook

Hackers Notebook

The Dungeon of Disk Management holds the kingdom’s treasures. To master Linux, you must not only cast commands but also guard the vaults where knowledge resides. Control the disks, and you control the persistence of the kingdom itself.

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Updated on Dec 28, 2025