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Mattscreative edited this page Dec 5, 2025 · 2 revisions

CachyOS Filesystem Management Guide

Complete beginner-friendly guide to filesystem management on CachyOS, including ext4, btrfs, xfs, mounting, formatting, and filesystem optimization.

Table of Contents

  1. Understanding Filesystems
  2. Common Filesystems
  3. Formatting Disks
  4. Mounting Filesystems
  5. Filesystem Maintenance
  6. Filesystem Optimization
  7. Troubleshooting

Understanding Filesystems

What is a Filesystem?

Filesystem organizes how data is stored on disk.

What it does:

  • Organizes files: Structures file storage
  • Manages space: Tracks used/free space
  • File metadata: Stores file information
  • Access control: Manages permissions

Why it matters:

  • Performance: Affects disk performance
  • Features: Different features per filesystem
  • Reliability: Data integrity
  • Compatibility: System compatibility

Common Filesystems

ext4

ext4 is the default Linux filesystem.

Features:

  • Mature: Stable and well-tested
  • Compatible: Works everywhere
  • Reliable: Good data integrity
  • Performance: Good performance

Best for:

  • General use: Most use cases
  • Stability: When reliability matters
  • Compatibility: Maximum compatibility

btrfs

btrfs is a modern filesystem.

Features:

  • Snapshots: System snapshots
  • Compression: Built-in compression
  • RAID: Software RAID support
  • Copy-on-write: Efficient storage

Best for:

  • Snapshots: System snapshots
  • Advanced features: Modern features
  • Storage efficiency: Compression

xfs

xfs is a high-performance filesystem.

Features:

  • Performance: High performance
  • Large files: Handles large files well
  • Scalability: Scales well
  • Journaling: Reliable journaling

Best for:

  • Performance: When speed matters
  • Large files: Large file handling
  • Servers: Server workloads

Other Filesystems

FAT32:

  • Use: USB drives, compatibility
  • Limitations: 4GB file size limit

NTFS:

  • Use: Windows compatibility
  • Features: Windows file system

exFAT:

  • Use: Large USB drives
  • Features: No file size limit

Formatting Disks

Check Disk

List disks:

lsblk

What this does:

  • Lists block devices
  • Shows disks and partitions
  • Helps identify disk

Check disk details:

sudo fdisk -l

What this does:

  • Shows detailed disk information
  • Lists partitions
  • Shows filesystem types

Format as ext4

Format partition:

sudo mkfs.ext4 /dev/sda1

What this does:

  • Formats partition as ext4
  • Creates ext4 filesystem
  • ** Erases all data!**

With label:

sudo mkfs.ext4 -L "MyDisk" /dev/sda1

What this does:

  • Formats with label
  • -L: Sets filesystem label
  • Easier identification

Format as btrfs

Format partition:

sudo mkfs.btrfs /dev/sda1

What this does:

  • Formats partition as btrfs
  • Creates btrfs filesystem
  • ** Erases all data!**

With compression:

sudo mkfs.btrfs -f -L "MyDisk" /dev/sda1

What this does:

  • Formats btrfs
  • -f: Force (overwrites existing)
  • -L: Sets label

Format as xfs

Format partition:

sudo mkfs.xfs /dev/sda1

What this does:

  • Formats partition as xfs
  • Creates xfs filesystem
  • ** Erases all data!**

Mounting Filesystems

Manual Mounting

Mount filesystem:

sudo mount /dev/sda1 /mnt

What this does:

  • Mounts partition to /mnt
  • Makes filesystem accessible
  • Temporary mount

Unmount:

sudo umount /mnt

What this does:

  • Unmounts filesystem
  • Safely removes mount
  • ** Don't unmount while in use**

Permanent Mounting

Edit fstab:

sudo nano /etc/fstab

Add entry:

UUID=xxxx-xxxx-xxxx /mnt ext4 defaults 0 2

What this means:

  • UUID: Partition UUID
  • /mnt: Mount point
  • ext4: Filesystem type
  • defaults: Mount options
  • 0 2: Dump and fsck options

Find UUID:

lsblk -f

What this does:

  • Shows filesystem UUIDs
  • Use UUID in fstab
  • More reliable than device names

Test fstab:

sudo mount -a

What this does:

  • Mounts all fstab entries
  • Tests configuration
  • Verifies fstab is correct

Filesystem Maintenance

Check Filesystem

Check ext4:

sudo fsck.ext4 /dev/sda1

What this does:

  • Checks filesystem integrity
  • Finds and fixes errors
  • ** Unmount first!**

Check btrfs:

sudo btrfs check /dev/sda1

What this does:

  • Checks btrfs filesystem
  • Verifies integrity
  • ** Read-only check**

Check xfs:

sudo xfs_repair /dev/sda1

What this does:

  • Checks and repairs xfs
  • Fixes filesystem issues
  • ** Unmount first!**

Filesystem Information

Show filesystem info:

df -h

What this does:

  • Shows filesystem usage
  • -h: Human-readable
  • Shows used/available space

Show inode usage:

df -i

What this does:

  • Shows inode usage
  • Helps identify inode issues
  • Important for many small files

Filesystem Optimization

ext4 Optimization

Mount options:

sudo mount -o noatime /dev/sda1 /mnt

What this does:

  • noatime: Don't update access times
  • Reduces disk writes
  • Better performance

Add to fstab:

UUID=xxxx /mnt ext4 defaults,noatime 0 2

btrfs Optimization

Enable compression:

sudo mount -o compress=zstd /dev/sda1 /mnt

What this does:

  • Enables zstd compression
  • Saves disk space
  • Good performance

Add to fstab:

UUID=xxxx /mnt btrfs defaults,compress=zstd 0 0

xfs Optimization

xfs is optimized by default:

  • Good performance out of the box
  • Few optimizations needed
  • Works well as-is

Troubleshooting

Filesystem Errors

Check filesystem:

sudo fsck.ext4 -f /dev/sda1

What this does:

  • Forces filesystem check
  • Finds and fixes errors
  • ** Unmount first!**

Auto-repair:

sudo fsck.ext4 -y /dev/sda1

What this does:

  • Auto-answers yes
  • Automatically repairs
  • ** Use carefully**

Mount Errors

Check mount point:

mountpoint /mnt

What this does:

  • Checks if mount point is mounted
  • Verifies mount status
  • Helps troubleshoot

Check fstab:

sudo mount -a

What this does:

  • Tests fstab entries
  • Shows mount errors
  • Helps fix fstab

Disk Space Issues

Check disk usage:

df -h

What this does:

  • Shows filesystem usage
  • Identifies full filesystems
  • Helps manage space

Find large files:

du -h --max-depth=1 / | sort -hr

What this does:

  • Shows directory sizes
  • Identifies large directories
  • Helps free space

Additional Resources

Summary

This guide covered:

  1. Understanding filesystems - What filesystems are
  2. Common filesystems - ext4, btrfs, xfs
  3. Formatting disks - Creating filesystems
  4. Mounting filesystems - Manual and permanent mounting
  5. Filesystem maintenance - Checking and repairing
  6. Filesystem optimization - Performance tuning
  7. Troubleshooting - Common filesystem issues

Key Takeaways:

  • ext4 is default and reliable
  • btrfs offers advanced features
  • xfs is high-performance
  • Use UUIDs in fstab for reliability
  • Check filesystems regularly
  • Optimize mount options for performance
  • Always unmount before checking/repairing

This guide is based on the CachyOS Wiki and Arch Linux Wiki and expanded with detailed explanations for beginners. For the most up-to-date filesystem information, always refer to the official documentation.

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