[Stepwise Guide] How to Recover Data from RAID Disk

What are the common causes of RAID data loss?

RAID (Redundant Array of Independent Disks) provides redundancy and protection against data loss, but it is not immune to failure. Data loss can still occur in RAID systems, often due to a variety of reasons. Here are some of the most common causes:

1. Hard drive failure

Single drive failure: In RAID levels like RAID 1, RAID 5, or RAID 6, a single disk failure might not lead to data loss, but it can trigger data degradation or reduced redundancy. However, if another disk fails before the damaged one is replaced or rebuilt, this can result in complete data loss.

Multiple drive failures: In RAID 0 and RAID 5, a failure of multiple drives can easily lead to data loss as the data is striped or distributed across multiple disks without enough redundancy.

2. RAID controller failure

The RAID controller manages the data distribution across drives in the array. If the RAID controller fails, it might not be able to read the data correctly, making the system unbootable or inaccessible. Sometimes, RAID controllers can be misconfigured, causing corruption or loss of data.

3. Corrupted RAID configuration

RAID configurations can get corrupted due to various reasons, including power surges, hardware failures, or software bugs. A corrupted RAID configuration can cause the array to become unreadable or lose data, especially if there is no backup.

4. Software or file system corruption

RAID arrays rely on a file system to organize and store data. If the file system becomes corrupted (e.g., due to software bugs, virus infections, or improper shutdowns), it may render the data inaccessible.

Corruption can also occur if the RAID management software is unstable or fails to properly communicate with the drives.

5. RAID rebuild failures

When a failed drive in a RAID 1, 5, or 6 array is replaced, the system rebuilds the array to restore redundancy. A failed rebuild process can cause data loss, especially if the new drive is not large enough or if multiple drives fail during the rebuild.

6. Incompatibility between drives

Using different makes, models, or sizes of drives in the same RAID array can lead to performance issues or incompatibility. In some cases, mismatched drives can result in data loss or array failure.

While RAID offers redundancy and protection, it is not a substitute for regular backups. It’s always a good practice to back up critical data separately to avoid catastrophic data loss.

How to recover data from RAID disk step by step 

1. Assess the situation

Before diving into the recovery process, it's important to assess the situation:

» Identify the RAID level: Understand whether your RAID is mirrored, striped, or using parity.

» Check the number of failed drives: RAID configurations allow for certain drives to fail without causing complete data loss, but if too many drives fail, recovery may be impossible.

Isolate the problem: Determine if the issue is due to a failed drive, a RAID controller issue, or a software problem.

2. Backup your remaining data

If you can still access the RAID array, make sure to back up any remaining data immediately. Data loss can be unpredictable, so the sooner you can back up the data, the better.

3. Determine the cause of the failure

Identifying the cause of failure can help in choosing the right recovery method:

» Hard drive failure: A single drive failure in RAID 1, 5, or 10 may be easy to replace.

» RAID controller failure: If the RAID controller is malfunctioning, swapping it out may restore access.

» Corruption or logical failure: If the RAID array is intact but you cannot access the data, logical recovery tools might be necessary.

4. Rebuild the RAID array (If applicable)

If a single drive has failed in a RAID 1, RAID 5, or RAID 10 array, you may be able to rebuild the RAID by replacing the failed disk:

» RAID 1: Replace the failed disk with a new one, and the RAID will mirror the data to the new drive.

» RAID 5: Replace the failed drive, and the RAID will reconstruct the lost data using the parity information.

» RAID 10: The process is similar to RAID 1; replace the failed disk and rebuild the array.

Always follow the RAID controller's manual or software instructions for the rebuild process.

5. Use data recovery software

If the RAID array cannot be rebuilt or if there is more extensive damage (e.g., multiple failed drives, corruption), you may need to use professional data recovery software. AOMEI FastRecovery is an advanced data recovery software designed to retrieve lost or deleted files from various storage devices, including RAID disks. This tool supports RAID 0, RAID 1, RAID 5, and other configurations, ensuring comprehensive coverage for different setups. Advantages of AOMEI FastRecovery

◆ High recovery success rate: Uses advanced algorithms to maximize recovery chances, even for corrupted or formatted RAID disks.
◆ Fast and deep scanning modes: Quickly detects recently deleted files or performs thorough scans to recover deeply buried data.
◆ File type versatility: Supports recovery of various file types, including lost documents, photos, videos, and more.
◆ Preview functionality: Allows users to preview recoverable files before restoration, ensuring the right data is recovered.
◆ Safe and secure: Guarantees a non-destructive process that protects the integrity of existing data on RAID arrays.
◆ Cross-device compatibility: Besides RAID, it supports recovering data from HDDs, SSDs, USB drives, and memory cards.

With its intuitive interface and advanced scanning algorithms, AOMEI FastRecovery helps users recover data quickly and effectively.

Step 1. Install and launch AOMEI FastRecovery. Choose the exact partition or disk where your data is lost and click Scan.

Step 2. Then, the recovery tool starts to scan and search. lt will execute the “Quickly Scan" first to find your deleted data fast, and then execute the “Deep Scan" for searching other lost data.

Step 3. Once the scan is completed, all deleted files, recycle bins and other missing files will be displayed. Please select the file you would like to recover and then click "Recover".

Step 4. Then, select a folder path to save your recovered files.

Step 5. Wait patiently for this process of recovery to end.

6. Seek professional data recovery services

If you are unable to recover the data yourself using software or hardware rebuilding, consider seeking professional data recovery services. Data recovery specialists have the tools and expertise to handle complex RAID recovery scenarios, including multiple drive failures or RAID array corruption. While this service can be costly, it may be your best option for retrieving critical data.

Conclusion

You now have a basic understanding of RAID data recovery. For common logical issues, AOMEI FastRecovery is a powerful tool that can help recover deleted files without effort. However, if the member disks in your RAID array are physically damaged, professional assistance is necessary.

It’s also crucial to remember that data recovery is not a substitute for proper backup practices. While a RAID array offers parity and redundancy, regular backups remain essential to protect against data loss.