How to recover data from Thecus N4820U-S/R NAS

Is your network drive gone, and you are wondering what to do? Has a RAID system crashed, and your files are no longer accessible? Does your device display an error while booting? Have you accidentally rebuilt your RAID system? Are several hard disks out of order?

How to recover data from NAS Thecus N4820U-S/R

Thecus N4820U-S/R NAS Data Recovery in 2024

In this step-by-step tutorial, we’ll show you how to rebuild your RAID and recover data from N4820U-S/R.

How to recover data from NAS Thecus N4820U-S/R

Recover data from damaged RAID arrays inaccessible from a computer.

Why can’t ordinary software tools restore files from RAID?

Conventional hard disks keep user’s data by writing it to their surface in a consecutive way, and this is how an entire file is stored on a single hard disk. However, when data is written to a RAID system, a file is divided into several parts. Then these parts are written consecutively to all hard disks within such array. The size of such parts may range from 2 KB to 2 MB, so each file is stored on several hard disks at the same time.

Such approach helps to speed up read and write operations, and it is evident that saving two parts of a file having the size of 1 GB to two hard disks simultaneously is much faster than saving the same 1 GB of data to one hard disk. However, this peculiarity makes file recovery more complicated.

Various RAID levels store information in different ways. Additionally, manufacturers like Thecus also introduce some modifications to this process, and that is why data can be written to hard disk in a wide variety of ways.

Can virtualization technologies impact data loss risks in NAS Thecus N4820U-S/R devices?

Yes, virtualization technologies can impact data loss risks in NAS Thecus N4820U-S/R devices.

Virtualization allows for the creation of virtual machines (VMs) that can run multiple operating systems and applications on a single physical server. By utilizing virtualization, users can isolate and separate different workloads, reducing the risk of data loss.

Here are a few ways virtualization technologies can impact data loss risks in NAS Thecus N4820U-S/R devices:

  1. Improved backup and disaster recovery: Virtualization allows for easy backup and restoration of VMs. Users can take snapshots of the VMs, creating a point-in-time copy of the entire system. In case of data loss or system failure, these snapshots can be used to quickly restore the VMs to a previous state, minimizing downtime and data loss.
  2. Enhanced data protection: Virtualization technologies often provide features like high availability and fault tolerance. These features ensure that if a physical server or storage device fails, the VMs can be automatically migrated to another server without interruption. This helps to protect against data loss caused by hardware failures.
  3. Data redundancy and replication: Virtualization allows for the creation of redundant storage systems. By replicating data across multiple NAS devices or using RAID configurations, data redundancy can be achieved, reducing the risk of data loss. In case of a hardware failure, the replicated data can be used to restore the system.
  4. Centralized management and monitoring: Virtualization technologies offer centralized management and monitoring tools. These tools provide a holistic view of the VMs and their associated storage devices, making it easier to identify and address any potential risks or issues that could lead to data loss.

While virtualization technologies can help mitigate data loss risks, it's important to note that they should be used in conjunction with other best practices, such as regular backups, secure access controls, and proper network security measures, to ensure comprehensive data protection.

How to take hard disks out of the NAS and connect them to a PC?

Although NAS N4820U-S/R can be accessed over the network, you still need to take the hard disks out of the storage device and connect them to a Windows computer. Only in this case will the software be able to scan them properly. Here is what you should do:

  1. Turn off the storage and disconnect it from the power supply.

    WARNING! Before you start taking hard disks out of your NAS device, read the manual carefully. Incorrect actions may damage your network-attached storage and/or the hard disks within the RAID system.

  2. Take the hard disks out of the NAS one by one, carefully removing them from their slots. Remember that the disks are extremely vulnerable: hitting or dropping them may result in serious physical damage.

  3. Make sure to mark each hard disk in accordance with how they were installed inside the NAS.

  4. Remove the hard disks and connect them to the computer. In this video, we have explored what ports are used to connect hard disks, and what to do if there are not enough ports or connectors.

    Go to view
    How to Order Remote Data Recovery

    How to Order Remote Data Recovery

Restoring data with Hetman RAID Recovery

Hetman Raid Recovery

This program recovers data from damaged RAID arrays and is fully compatible with Thecus N4820U-S/R. The hard disks that make up the RAID contain technical information about the algorithm used to save files. When launched, Hetman RAID Recovery reads this information and puts the damaged array together. Then you can open the disk and save your files. Also, you can recover the files accidentally deleted from the network drive.

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How to recover data from a Thecus

How to recover data from a Thecus

N4820U-S/R has 4 HDD slots, and it supports the following array types:

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

NAS supports:

  • EXT3;
  • EXT4;
  • XFS;

Safe recovery from disk images

This utility lets you save an entire copy of the disk to file and then work with this image instead of the actual disk. Such feature helps to protect data on the disk from:

  • Overwriting during the recovery process;
  • Loss resulting from bad sectors;
  • User mistakes.

To create an image, do the following:

  1. Make sure that you have enough free space to save the image. The image file size usually equals the disk size.

  2. Select the disk in the main window, and choose from the menu ToolsSave Disk. You can select multiple disks to be saved.

  3. When the image creation wizard starts, you can choose to save the entire disk or select only a part of it. Specify the parameters and click Next.

    Hetman Raid Recovery: Image Creation Wizard
  4. At this stage, you need to choose a directory where to save the image. Choose any disk connected to this PC, or save the image by FTP.

    Hetman Raid Recovery: hoose any disk connected to this PC, or save the image by FTP

Where are user’s files stored?

The Thecus N4820U-S/R 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.

Comparison of software for RAID recovery

Product Operating system License type RAID controller support Supported file systems Virtual RAID controller support Data recovery from damaged RAID File preview
Hetman RAID Recovery Windows Paid Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
DiskInternals RAID Recovery Windows Paid Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ No Yes Yes
R-Studio Windows, Mac, Linux Paid Yes, over 200 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
UFS Explorer RAID Recovery Windows, Mac, Linux Paid Yes, over 1,000 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
EaseUS Data Recovery Windows Paid Yes, over 20 controllers FAT, NTFS, Ext2/3/4, HFS+ No Yes Yes
ReclaiMe Free RAID Recovery Windows Free Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes


We will be happy to answer your questions!

Comments (3)

  • Hetman Software: Data Recovery
    Hetman Software: Data Recovery 9.08.2022 12:31 #
    If you want to ask a question about data recovery, from NAS N4820U-S/R, feel free to leave a comment!
  • Patsy Scoggins
    Patsy Scoggins 12.09.2023 23:57 #
    Is it possible to recover data from a NAS Thecus N4820U-S/R device that has undergone a factory reset or system restore?
    • Hetman Software
      Hetman Software 13.09.2023 01:00 #

      It is generally not possible to recover data from a NAS device that has undergone a factory reset or system restore. A factory reset or system restore erases all data and settings on the device and restores it to its original factory state. This process typically involves formatting the storage drives, which permanently deletes all data stored on them.

      If you have a backup of your data, you can restore it from the backup after the factory reset or system restore. However, if you do not have a backup, it is unlikely that you will be able to recover the data. It is always recommended to regularly backup important data to avoid data loss in such situations.

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Vladimir Artiukh

Author: Vladimir Artiukh, Technical Writer

Vladimir Artiukh is a technical writer for Hetman Software, as well as the voice and face of their English-speaking YouTube channel, Hetman Software: Data Recovery for Windows. He handles tutorials, how-tos, and detailed reviews on how the company’s tools work with all kinds of data storage devices.

Oleg Afonin

Editor: Oleg Afonin, Technical Writer

Oleg Afonin is an expert in mobile forensics, data recovery and computer systems. He often attends large data security conferences, and writes several blogs for such resources as, Elcomsoft and Habr. In addition to his online activities, Oleg’s articles are also published in professional magazines. Also, Oleg Afonin is the co-author of a well-known book, Mobile Forensics - Advanced Investigative Strategies.


Questions and answers

  • What are the key features and specifications of the NAS Thecus N4820U-S/R that make it suitable for use as a website server?

    The Thecus N4820U-S/R is a network-attached storage (NAS) device that offers several key features and specifications that make it suitable for use as a website server. These include:

    1. High-performance hardware: The NAS is powered by an Intel Celeron N3160 quad-core processor, which provides sufficient processing power for running web server applications and handling website traffic.
    2. Large storage capacity: The N4820U-S/R comes with four drive bays that support 3.5" SATA hard drives, allowing for a large storage capacity of up to 40TB (with 10TB drives). This enables hosting multiple websites and storing large amounts of data.
    3. Redundant power supply: The NAS is equipped with a redundant power supply, ensuring uninterrupted operation even in the event of a power supply failure. This feature is crucial for maintaining website availability and minimizing downtime.
    4. Dual LAN ports: The device offers dual Gigabit Ethernet ports, allowing for link aggregation and failover support. This enables increased network bandwidth and ensures network connectivity even if one port or cable fails.
    5. RAID support: The N4820U-S/R supports various RAID levels (0, 1, 5, 6, 10, and JBOD), providing data redundancy and protection against drive failures. This is essential for maintaining website data integrity and minimizing the risk of data loss.
    6. Virtualization support: The NAS supports virtualization technologies such as VMware and Citrix, allowing for the creation and management of virtual machines. This feature is useful for running website development and testing environments within the NAS itself.
    7. Robust security features: The device offers multiple security features, including AES 256-bit encryption, antivirus protection, and data backup/replication options. These features help protect website data from unauthorized access, malware, and potential data loss.
    8. Scalability: The N4820U-S/R supports expansion via additional external storage devices, allowing for increased storage capacity as website requirements grow over time.

    Overall, the combination of powerful hardware, ample storage capacity, redundant power supply, network connectivity options, RAID support, virtualization capabilities, and robust security features make the Thecus N4820U-S/R a suitable choice for hosting websites and serving web content.

  • How does the NAS Thecus N4820U-S/R facilitate website hosting and management, and what software or tools are included?

    The NAS Thecus N4820U-S/R is a network-attached storage device that can facilitate website hosting and management through various software and tools. Here are some features and capabilities of the NAS that enable website hosting:

    1. Web Server: The NAS comes with a built-in web server that allows you to host websites directly on the device. It supports popular web server software like Apache, PHP, and MySQL.
    2. Web Disk: The NAS provides a web-based file management system called Web Disk. It allows you to access and manage your website files through a web browser, making it easy to upload, download, and edit files.
    3. FTP Server: The NAS includes an FTP server that enables you to transfer files to and from the device. This is useful for uploading website files or granting access to clients or collaborators.
    4. Virtual Host: The NAS supports virtual hosting, allowing you to host multiple websites on a single device. You can configure different domain names and assign specific directories for each website.
    5. CMS Support: The NAS is compatible with popular content management systems (CMS) like WordPress, Joomla, and Drupal. You can install these CMS platforms using the NAS's App Center, which provides a range of applications for website management.
    6. Backup and Restore: The NAS offers various backup and restore options to protect your website data. It supports scheduled backups, incremental backups, and remote replication to other NAS devices or cloud storage services.
    7. RAID Support: The NAS supports RAID configurations, which provide data redundancy and improve website uptime. RAID protects against data loss in case of hard drive failures.
    8. Security Features: The NAS includes security features like HTTPS support, IP blocking, and antivirus scanning to protect your website from potential threats.
    9. DNS Server: The NAS can act as a DNS server, allowing you to manage domain name resolution for your hosted websites.
    10. Monitoring and Management: The NAS provides a web-based management interface where you can monitor system status, configure network settings, and manage user access.

    Overall, the NAS Thecus N4820U-S/R offers a comprehensive set of tools and software to facilitate website hosting and management, making it a suitable solution for small to medium-sized businesses or individuals looking to host their websites.

  • Can the NAS Thecus N4820U-S/R handle high traffic and multiple websites simultaneously, and what are the potential limitations or scalability options for website hosting on this device?

    The NAS Thecus N4820U-S/R is primarily designed for file storage and sharing purposes rather than website hosting. While it can handle moderate website hosting and some traffic, it may not be suitable for high traffic or hosting multiple websites simultaneously.

    The potential limitations for website hosting on this device include:

    1. Limited processing power: The N4820U-S/R is equipped with a quad-core Intel Celeron processor, which may not be powerful enough to handle heavy website traffic or multiple websites simultaneously.
    2. Limited RAM: It comes with 4GB of DDR3 RAM, which can limit the number of concurrent website visitors and the overall performance of the hosted websites.
    3. Lack of specialized features: The NAS lacks specific features and optimizations typically found in dedicated web hosting solutions, such as caching mechanisms, load balancing, and advanced security options.
    4. Network bandwidth: The NAS has four Gigabit Ethernet ports, which can limit the network throughput and the number of simultaneous connections.

    Scalability options for website hosting on this device are limited. While you can potentially upgrade the RAM to its maximum supported capacity of 8GB, it may not significantly improve the hosting capabilities. Additionally, the device's processing power and network bandwidth cannot be upgraded.

    If you require high traffic handling and hosting multiple websites simultaneously, it is recommended to consider dedicated web hosting solutions or more powerful NAS devices specifically designed for web hosting purposes.

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