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Disk failures and lost partitions can lead to boot failures, data loss, and extended downtime in Linux systems. Whether due to accidental deletion, filesystem corruption, or hardware failure, knowing how to diagnose and recover disk partitions is critical for system administrators and DevOps engineers.

📌 In this guide, you will learn:
✅ How to diagnose disk failures & missing partitions
✅ Step-by-step recovery methods using fdisk, parted, and testdisk
✅ Enterprise case studies on real-world partition loss
✅ Best practices to prevent disk failures and data loss

🔜 Next in the series: Troubleshooting RAID Failures & Recovery Techniques

🔍 1. Understanding Linux Disk Failures & Lost Partitions

📌 Common Causes of Disk & Partition Loss

🔍 2. Diagnosing Disk & Partition Issues

📌 Step 1: Check Disk Health & Errors

Before attempting recovery, check if the disk is physically damaged:

🔹 Verify disk connectivity and partitions:

lsblk
fdisk -l
parted -l

📌 Expected Output Example:

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0   500G  0 disk 
├─sda1   8:1    0   500M  0 part /boot
├─sda2   8:2    0   50G   0 part /

💡 If partitions do not appear, the partition table may be corrupted or deleted.

🔹 Check for bad sectors on the disk:

smartctl -a /dev/sda

📌 Expected Output:

SMART overall-health self-assessment test result: PASSED

💡 If the test fails, the disk may be physically damaged.

🔍 3. Repairing Disk & Partition Issues

💡 Below are recovery methods for common disk partition failures.

🛠️ Fix 1: Recover Lost Partitions Using testdisk

If a partition was accidentally deleted, testdisk can help recover it.

1️⃣ Install testdisk:

sudo apt install testdisk   # Debian/Ubuntu
sudo yum install testdisk   # CentOS/RHEL

2️⃣ Launch testdisk and select the affected disk:

sudo testdisk

3️⃣ Choose "Analyze" → Select "Quick Search"
4️⃣ Identify and restore the lost partition
5️⃣ Write changes and reboot:

reboot

📌 Expected Outcome: If successful, the lost partition will be restored.

🛠️ Fix 2: Repair Corrupt Filesystems with fsck

If the partition exists but is unreadable, use fsck to repair filesystem corruption.

1️⃣ Run fsck in emergency mode:

fsck -y /dev/sda2

📌 Command Breakdown:

• fsck → Checks and repairs filesystem errors
• -y → Automatically accepts fixes

2️⃣ Remount the filesystem:

mount -o remount,rw /dev/sda2

📌 Expected Outcome: If successful, the filesystem will be repaired and mounted correctly.

🛠️ Fix 3: Restore Partition Table with parted

If the partition table is corrupted, use parted to recreate it.

1️⃣ Launch parted:

sudo parted /dev/sda

2️⃣ Check for partitions:

print

3️⃣ If the partition table is missing, recreate it:

mklabel gpt
mkpart primary ext4 1MiB 100%
quit

📌 Expected Outcome: The partition table will be restored.

🛠️ Fix 4: Reinstall GRUB on a Corrupt Bootloader

If GRUB fails to detect partitions, reinstall it:

1️⃣ Boot into a Linux Live USB
2️⃣ Mount the root partition:

mount /dev/sda2 /mnt

3️⃣ Chroot into the system:

chroot /mnt

4️⃣ Reinstall GRUB:

grub2-install /dev/sda
grub2-mkconfig -o /boot/grub2/grub.cfg

5️⃣ Reboot the system:

exit
reboot

📌 Expected Outcome: If successful, GRUB will detect all partitions.

🔍 4. Enterprise Case Study: Data Recovery After Partition Loss

📌 Scenario:
A financial services company accidentally deleted a key partition on a production database server.

📌 Symptoms:

• The server refused to boot (No such partition)
• Running fdisk -l showed missing partitions
• The database was inaccessible, causing an outage

📌 Investigation:

• Engineers used a Live USB to inspect disk structure
• testdisk detected deleted partitions
• The partition table was corrupt, preventing boot

📌 Solution:
🔹 Used testdisk to restore the deleted partition
🔹 Ran fsck -y /dev/sda2 to repair filesystem errors
🔹 Reinstalled GRUB to detect and boot into the restored partition

📌 Lesson Learned:
⚠️ Always backup partition tables before making changes
⚠️ Use LVM snapshots for rapid recovery
⚠️ Automate disk monitoring with smartctl

🔍 5. Best Practices to Prevent Disk Failures

📌 To minimize disk-related failures, follow these best practices:

✅ Enable disk health monitoring (smartctl -a /dev/sda)
✅ Schedule periodic fsck checks to prevent filesystem corruption
✅ Keep multiple backups of partition tables (sfdisk -d /dev/sda > backup.txt)
✅ Use RAID for redundancy in production environments
✅ Automate disk failure alerts with monitoring tools (Prometheus, Zabbix)

📌 Summary

💡 Want to learn more? Check out the next article: "Troubleshooting RAID Failures & Recovery Techniques" 🚀

💬 Join the Discussion!

💬 Have you experienced partition loss or disk failure in production?
💡 What strategies do you use to prevent data loss?
🚀 Share your experience in the comments!

📌 Next Up: Troubleshooting RAID Failures & Recovery Techniques

🔜 Continue to the next guide in this series!

📩 Would you like a downloadable PDF version of this guide? Let me know! 🚀