How to Recover Data from a Failing Linux System
Aug 01, 2025 am 04:20 AMStop using the faulty system immediately to prevent further corruption; 2. Use Live USB/CD to boot into a read-only environment; 3. Determine the fault type: physical corruption requires avoiding repeated power-on and considering professional recovery or using ddrescue cloning. File system logic errors can try FSK repair or read-only mount, and boot problems can be accessed directly through the Live environment; 4. Priority is given to using ddrescue to complete cloning of the faulty disk to protect the original data before recovery; 5. Mount the partition from the cloned disk or Live environment and use cp or rsync to copy the data to external storage; 6. For deleted or seriously damaged files, use TestDisk to restore the partition or PhotoRec according to file characteristics; 7. If the system uses LUKS or LVM, the encrypted volume must be unlocked and the logical volume must be activated before mounting. The entire process should always prioritize data security, avoid writing to the original disk, ensure data extraction is completed under stable conditions, and finally back up the recovered data to multiple locations to ensure security.
If your Linux system is failing—whether due to a corrupted filesystem, failing hard drive, or boot issues—recovering your data should be the top priority. Acting quickly and correctly can mean the difference between a full recovery and permanent data loss. Here's how to approach data recovery from a failing Linux system.

1. Stop Using the Failing System Immediately
As soon as you notice signs of failure (slow performance, frequent crashes, I/O errors, strange noises from the drive), shut down the system if it's safe to do so and avoid further writes to the disk. Every operation risks worsening the damage, especially on a physically failing drive.
Why? Continued use can overwrite data or push a marginal drive over the edge.
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2. Boot from a Live USB/CD
Use a Linux live environment (like Ubuntu, SystemRescue, or Clonezilla) to access your system without mounting or altering the internal drive.
Steps:

- Create a bootable Linux USB on another machine.
- Boot the failing system from the USB.
- Choose “Try Ubuntu” or equivalent to enter a live session.
This keeps your internal drive read-only until you're ready, minimizing risk.
3. Assess the Type of Failure
Different problems require different approaches.
A. Physical Drive Failure (Clicking, Grinding, Not Detected)
- Signs: BIOS doesn't detect drive, strange noises, SMART errors.
- Action:
- Do not repeatedly power on the drive.
- Consider professional data recovery services if the data is critical.
- If attempting DIY, use
ddrescue
to clone the drive before further access.
B. Logical/Filesystem Corruption (System boots but crashes, can't mount partitions)
-
Use
fsck
cautiously:sudo fsck /dev/sda1
Only run
fsck
on unmounted partitions. Backup first if possible. Check mountability:
sudo mkdir /mnt/recovery sudo mount /dev/sda1 /mnt/recovery
If mount fails, try read-only:
sudo mount -o ro /dev/sda1 /mnt/recovery
C. Bootloader or Kernel Issues (Can't boot but data may be intact)
- Often, the data is fine. Boot from live USB and directly access the filesystem to copy files.
4. Clone the Drive Before Recovery (Highly Recommended)
If the drive shows any instability, clone it first using ddrescue
:
sudo ddrescue /dev/sda /dev/sdb rescue.log
-
/dev/sda
= failing drive -
/dev/sdb
= healthy target drive (same size or larger) -
rescue.log
tracks progress and allow retries
ddrescue
is designed for failing drives—it retries bad sectors and skips around errors.
5. Recover Data from the Clone or Live Environment
Once you have a stable environment or a cloned drive:
- Mount the partition:
sudo mount /dev/sdb1 /mnt/recovery
- Copy data to an external drive:
cp -r /mnt/recovery/home /path/to/external/drive/
Or use
rsync
for better control:rsync -av --progress /mnt/recovery/home/ /external-drive/backup/
Use
rsync
with--ignore-errors
if some files are unreadable.
6. Use Data Recovery Tools for Deleted or Inaccessible Files
If files were deleted or filesystem is badly damaged:
TestDisk : Recovers lost partitions.
sudo testdisk /dev/sda
PhotoRec : Recovers files by content (works even without a filesystem).
- Recovers photos, documents, archives, etc., by scanning raw data.
- Available with TestDisk.
7. Handle Encrypted or LVM Systems
If you used LUKS encryption or LVM:
- Unlock encrypted partition:
sudo cryptsetup luksOpen /dev/sda2 cryptroot sudo vgscan sudo vgchange -ay sudo mount /dev/mapper/vg-name-root /mnt/recovery
You'll need the passphrase or recovery key.
Final Tips
- Always work on a copy when possible.
- Use external power for USB enclosures —underpowered drives can cause read errors.
- Label and organize recovered data immediately.
- Back up recovered data to multiple locations.
Basically, the key is to avoid making things worse. Use a live system, clone if in doubt, and prioritize data extraction over fixing the system. With careful steps, most data can be saved—even from a dying drive.
The above is the detailed content of How to Recover Data from a Failing Linux System. For more information, please follow other related articles on the PHP Chinese website!

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