File system corruption can strike any Linux system unexpectedly – from sudden power loss to faulty hardware. Don’t panic! This guide walks you through detection and repair with practical steps.
🚨 Symptoms of Corruption
- “Input/output error” messages
- Unmountable drives or refusal to mount
- Missing files/folders
- System freezing during disk access
dmesglogs showing “EXT4-fs error” or similar- Applications crashing when accessing files
🔒 Critical First Steps
- STOP WRITING DATA: Avoid further writes to prevent permanent loss.
- Unmount the partition:
sudo umount /dev/sdXY # Replace sdXY with your partition (e.g., sda1) - Use a Live USB: If the OS won’t boot, use Ubuntu Live USB to work offline.
🔧 Repair Tools by File System Type
| File System | Repair Tool | Command Example |
|---|---|---|
| EXT2/3/4 | fsck |
sudo fsck -y /dev/sdXY |
| XFS | xfs_repair |
sudo xfs_repair /dev/sdXY |
| Btrfs | btrfs check |
sudo btrfs check --repair /dev/sdXY |
| FAT/NTFS | ntfsfix |
sudo ntfsfix /dev/sdXY |
⚙️ Step-by-Step Repair (EXT4 Example)
- Force a filesystem check on reboot:
sudo touch /forcefsck # For systems that can still boot sudo reboot - Manual repair with
fsck:sudo fsck -C -y -f /dev/sdXY # -C: Progress bar, -y: Auto-fix, -f: Force check - Analyze logs:
sudo dmesg | grep -i "error\|fsck\|sdXY"
⚠️ Handling Severe Corruption
- If
fsckasks to repair primary superblock, use backup superblocks:sudo mkfs.ext4 -n /dev/sdXY # Find backup superblock addresses (DO NOT use -n and -y together!) sudo fsck -b 32768 /dev/sdXY # Replace 32768 with your backup block - For unrecoverable inodes:
sudo debugfs /dev/sdXY→dump ~/recovered_file
🛡️ Prevention Best Practices
- Regular backups: Use
rsyncor BorgBackup. - UPS: Protect against power surges.
- Schedule checks:
sudo tune2fs -c 30 /dev/sdXY # Check every 30 mounts - Enable journaling: Always use journaled filesystems (ext4/XFS) for critical data.
💡 When All Else Fails
- PhotoRec/TestDisk: Recover raw files from damaged partitions.
- Professional help: For mission-critical data, consult recovery services.
Final Tip: Never run fsck on a mounted drive! Always unmount first. Stay calm, work methodically, and let the tools do their job. Your data has a fighting chance! 🛠️💾
> ℹ️ Remember: File system repair isn’t data recovery. If valuable data is at risk, image the drive with ddrescue first:
> sudo ddrescue /dev/sdXY ~/disk.img ~/logfile