How to Extract Data from a RAID Disk When NAS TerraMaster U8-420 is Not Booting Up

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS TerraMaster U8-420
• How to Remove Hard Disks from Your NAS and Connect Them to a PC
  • Step-by-Step Data Recovery with Hetman RAID Recovery
  • How to Safely Recover Data from Disk Images
  • Where Are the User’s Files Actually Stored?
  • RAID Recovery Software: Detailed Comparison

Why Regular Data Recovery Tools Can’t Restore Files from RAID

Conventional hard drives store user data by writing it sequentially across the disk surface, which means an entire file is typically located on a single drive. In contrast, when data is written to a RAID array, each file is split into multiple fragments. These fragments are then distributed and written in sequence across all the drives in the array. Depending on the configuration, fragment sizes can range from 2 KB to 2 MB, so every file is physically stored across several disks at once.

This approach significantly increases read and write performance — after all, writing two halves of a 1 GB file to two drives simultaneously is much faster than writing the full 1 GB to a single disk. However, this same mechanism makes file recovery far more complex.

Different RAID levels use different methods to distribute and protect data. On top of that, manufacturers like TerraMaster often add their own proprietary structures and variations. As a result, data can be written to disks in many different formats, and each requires a specific approach during recovery.

How can RAID (Redundant Array of Independent Disks) configurations impact data loss in NAS TerraMaster U8-420 devices?

RAID configurations can have a significant impact on data loss in NAS TerraMaster U8-420 devices. Here are a few ways RAID can affect data loss:

1. Redundancy: RAID configurations, such as RAID 1, RAID 5, or RAID 6, provide redundancy by distributing data across multiple disks. In the event of a disk failure, the redundant data allows for the reconstruction of lost data. This reduces the risk of data loss as long as the failed disk is replaced and the array is rebuilt promptly.
2. Data protection: RAID configurations offer various levels of data protection. For example, RAID 1 mirrors data across two disks, ensuring that if one disk fails, the other contains an exact copy. Similarly, RAID 5 and RAID 6 use parity information to protect against a single or multiple disk failures. These configurations enhance data integrity and minimize the chances of data loss.
3. Hot-swapping: Many NAS devices, including TerraMaster U8-420, support hot-swapping, which allows for the replacement of a failed disk without shutting down the system. This feature reduces the downtime during disk replacement and ensures continuous data availability.
4. Rebuild process: When a failed disk is replaced, the RAID array initiates a rebuild process to restore data redundancy. During this process, data is reconstructed from the remaining disks or parity information. However, the rebuild process can be resource-intensive and time-consuming, increasing the risk of data loss if another disk fails during the rebuild. It is crucial to monitor the rebuild process and address any issues promptly.
5. RAID controller failure: While RAID configurations provide data protection against disk failures, they are still vulnerable to RAID controller failures. If the RAID controller malfunctions, it can lead to data loss or corruption across the entire array. Regular backups and monitoring of the RAID controller's health are essential to mitigate this risk.

Overall, RAID configurations in NAS TerraMaster U8-420 devices can significantly reduce the risk of data loss by providing redundancy, data protection, and hot-swapping capabilities. However, it is important to regularly monitor the array's health, promptly replace failed disks, and maintain backups to ensure data integrity and minimize the impact of potential failures.

How to Remove Hard Disks from Your NAS and Connect Them to a PC

Although the NAS U8-420 can be accessed over the network, you still need to remove its hard disks and connect them directly to a Windows PC. Only then can the recovery software properly scan and analyze the drives. Follow these steps:

1. Power off the NAS and disconnect it from the power source.

   WARNING! Before removing any drives, carefully read the device manual. Improper actions may damage both the NAS enclosure and the hard disks in the RAID array.

2. Remove the hard disks one by one, gently sliding each drive out of its slot. Remember that hard disks are highly sensitive: any impact or drop can cause serious physical damage.

3. Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.

4. Connect the drives to your computer. In this video, we explain which ports you can use to connect hard disks and what to do if your PC does not have enough free connectors.

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   How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with TerraMaster U8-420. Each hard disk in the array contains technical metadata describing how files were written. When launched, Hetman RAID Recovery analyzes this metadata, automatically reconstructs the damaged array, and provides access to its contents. After that, you can browse the recovered disk and save your files. The program can also restore files that were accidentally deleted from the network drive.

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How to recover data from a TerraMaster

U8-420 has 8 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 50;
• RAID 60;
• JBOD;

NAS supports:

• Ext2;
• Ext3;
• Ext4;
• Btrfs;

How to Safely Recover Data from Disk Images

This utility allows you to create a complete copy of a disk and work with the disk image instead of the physical drive. This approach helps protect your data from:

• Overwriting during the recovery process;
• Additional data loss caused by bad sectors;
• User errors.

To create a disk image, follow these steps:

1. Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.

2. In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.

3. When the Image Creation Wizard opens, select whether you want to save the entire disk or only a specific region. Adjust the settings and click Next.

   

4. Choose the directory where the image will be saved. You may select any available disk connected to your PC or upload the image via FTP.

   

Where Are the User’s Files Actually Stored?

The TerraMaster U8-420 network-attached storage keeps OS Linux operating system files on a separate RAID 1 (mirrored) array. Usually, all NAS systems create several volumes on every hard disk, and the first of them takes up to 2 Gb of space. This is where operating system files are stored. Other volumes are united into a RAID array where user’s data is written.

RAID Recovery Software: Detailed Comparison