RAID Array Recovery on NAS Thecus N16000V: Best Practices When It Breaks

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Thecus N16000V
• 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 Thecus 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 a NAS Thecus N16000V device's caching policy impact data loss risks?

The caching policy of a NAS (Network Attached Storage) device like Thecus N16000V can have an impact on data loss risks in the following ways:

1. Write Caching: Write caching is a feature that allows the NAS device to temporarily store write operations in cache memory before writing them to the actual storage disks. While write caching can improve performance, it also introduces a risk of data loss in case of power failure or system crash before the data is written to the disks. If the caching policy prioritizes performance over data integrity, the risk of data loss increases.
2. Read Caching: Read caching involves storing frequently accessed data in cache memory to speed up subsequent read operations. While read caching can significantly improve performance, it can also introduce a risk of data loss if the cached data becomes outdated or corrupted. If the caching policy does not prioritize data consistency and integrity, there is a higher risk of data loss.
3. Cache Synchronization: In a multi-node or clustered NAS environment, where multiple NAS devices are connected and share data, cache synchronization becomes crucial. If the caching policy does not ensure proper synchronization of cached data across all nodes, there is a risk of data inconsistency and potential data loss when accessing data from different nodes.
4. Cache Failure: Caches, whether write or read, can fail due to various reasons such as hardware issues or software errors. If the caching policy does not have proper mechanisms to handle cache failures, it can lead to data loss or corruption.

To mitigate data loss risks associated with caching policies, it is important to consider the following:

• Choose a caching policy that balances performance and data integrity based on your specific needs. Some NAS devices offer configurable caching policies, allowing you to adjust the balance according to your requirements.
• Implement mechanisms like battery backup units (BBUs) or uninterruptible power supplies (UPS) to ensure that cached data is not lost in case of power failures.
• Regularly monitor and test the cache functionality to identify any potential issues or failures.
• Implement cache synchronization mechanisms in multi-node or clustered NAS environments to ensure data consistency across all nodes.
• Regularly backup your data to an external storage device or off-site location to mitigate the impact of data loss in case of cache failures or other unforeseen circumstances.

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

Although the NAS N16000V 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.

   Go to view

   

   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 Thecus N16000V. 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.

Go to view

How to recover data from a Thecus

N16000V has 16 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 50;
• RAID 60;
• RAID 10;
• JBOD;

NAS supports:

• EXT3;
• EXT4;
• XFS;

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 Thecus N16000V 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