How to Extract Data from a RAID Disk When NAS TerraMaster F8-421 Fails to Power On

Has your NAS TerraMaster F8-421 suddenly lost its network drive and you’re unsure what to do next? Did the RAID array collapse, making your files inaccessible? Is the device throwing errors during startup? Perhaps you accidentally rebuilt the RAID array or several hard drives failed at the same time?

How to Extract Data from a RAID Disk When NAS TerraMaster F8-421 Fails to Power On

TerraMaster F8-421 NAS Data Recovery in 2025

In this step-by-step tutorial, we’ll show you how to rebuild your RAID and recover data from an F8-421. We’ll walk through the most common causes of failure and demonstrate proven methods to restore files from a lost or degraded RAID array.

How to Extract Data from a RAID Disk When NAS TerraMaster F8-421 Fails to Power On

RAID Recovery™ 2.8
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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.

Can remote access to NAS TerraMaster F8-421 devices pose additional data loss risks?

Remote access to NAS TerraMaster F8-421 devices can potentially pose additional data loss risks if not properly secured. Here are some factors to consider:

  1. Security vulnerabilities: Enabling remote access exposes the NAS device to potential security vulnerabilities. If the device is not adequately protected with strong passwords, firewall settings, and regular security updates, it may become an easy target for hackers.
  2. Unauthorized access: Remote access increases the chances of unauthorized users gaining access to your NAS device. If someone gains unauthorized access, they may be able to delete, modify, or steal your data, leading to potential data loss.
  3. Network vulnerabilities: Remote access relies on network connectivity, which introduces additional risks. If the network is not properly secured, it may be susceptible to attacks like man-in-the-middle attacks, where an attacker intercepts the communication between the remote device and the NAS device, potentially leading to data loss.
  4. Human error: Remote access increases the likelihood of human errors that can result in data loss. For example, accidental deletion or misconfiguration of settings while accessing the NAS remotely can lead to irreversible data loss.

To mitigate these risks, it is important to follow best practices for securing remote access to NAS devices:

  • Use strong passwords and enable two-factor authentication.
  • Regularly update the NAS firmware and security patches.
  • Configure firewall settings to restrict access to trusted IP addresses.
  • Enable encryption for remote connections using protocols like SSL or VPN.
  • Regularly backup your data to an off-site location to minimize the impact of data loss.

By implementing these security measures, you can reduce the potential risks associated with remote access to NAS TerraMaster F8-421 devices and protect your data from loss.

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

Although the NAS F8-421 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

    How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

Hetman Raid Recovery

This program restores data from damaged RAID arrays and is fully compatible with TerraMaster F8-421. 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 TerraMaster

How to recover data from a TerraMaster

F8-421 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.

    Hetman RAID Recovery: Image Creation Wizard
  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.

    Hetman RAID Recovery: Choose a disk or save the image via FTP

Where Are the User’s Files Actually Stored?

The TerraMaster F8-421 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

Product Operating system RAID controller support Supported file systems Virtual RAID controller support Data recovery from damaged RAID File preview
Hetman RAID Recovery Windows, Linux, MacOS Yes, over 100 controllers FAT, exFAT, NTFS, ReFS, APFS, HFS+, Ext4, Ext3, Ext2, ReiserFS, Btrfs, VMFS, Hikvision, XFS, UFS, ZFS Yes Yes Yes
DiskInternals RAID Recovery Windows Yes, over 10 controllers FAT, NTFS, Ext2/3/4, HFS+ No Yes Yes
R-Studio Windows, Mac, Linux Yes, over 20 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
UFS Explorer RAID Recovery Windows, Mac, Linux Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes
EaseUS Data Recovery Windows Yes, over 20 controllers FAT, NTFS, Ext2/3/4, HFS+ No Yes Yes
ReclaiMe Free RAID Recovery Windows Yes, over 100 controllers FAT, NTFS, Ext2/3/4, HFS+ Yes Yes Yes

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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 F8-421, feel free to leave a comment!
  • Zayden Mercer
    Zayden Mercer 10.09.2023 11:57 #
    Can data recovery from a NAS TerraMaster F8-421 device be performed if there are issues with the network protocols or settings?
    • Hetman Software
      Hetman Software 10.09.2023 12:59 #

      Yes, data recovery from a NAS TerraMaster F8-421 device can still be performed even if there are issues with the network protocols or settings. In such cases, you can try the following steps:

      1. Connect the NAS device directly to a computer using an Ethernet cable.
      2. Ensure that both the computer and NAS device are on the same network subnet (e.g., set the computer's IP address to a compatible subnet).
      3. Access the NAS device's web interface by entering its IP address in a web browser.
      4. If you can access the web interface, navigate to the network settings and verify or reconfigure the network protocols and settings to resolve any issues.
      5. If you're unable to access the web interface, try resetting the NAS device to its factory settings. This will erase all configurations, but it may resolve any network-related issues.
      6. Once the network issues are resolved, you can attempt data recovery using the NAS device's built-in recovery tools or by connecting the hard drives to a computer using a SATA-to-USB adapter.

      If you're not familiar with network troubleshooting or data recovery processes, it's recommended to seek assistance from a professional or the TerraMaster support team to avoid any potential data loss or further complications.

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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 xaker.ru, 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.

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Questions and answers

  • What are the key features and mechanisms that the NAS TerraMaster F8-421 offers to ensure file access security?

    The NAS TerraMaster F8-421 offers several key features and mechanisms to ensure file access security. Some of these include:

    1. User Access Control: The NAS provides comprehensive user access control, allowing administrators to create and manage user accounts with different access levels and permissions. This ensures that only authorized users can access specific files or folders.
    2. Folder Permissions: Administrators can set granular folder-level permissions, allowing them to control who can read, write, or delete files within specific folders. This helps in restricting access to sensitive data.
    3. HTTPS and SSL/TLS Encryption: The NAS supports HTTPS (Hypertext Transfer Protocol Secure) and SSL/TLS (Secure Sockets Layer/Transport Layer Security) encryption protocols. This ensures that all data transferred between the NAS and connected devices is encrypted, preventing unauthorized interception or access.
    4. IP Access Control: The NAS allows administrators to set up IP access control lists, defining which IP addresses or IP ranges are allowed or denied access to the NAS. This helps in restricting access to specific networks or devices.
    5. Two-Factor Authentication (2FA): The NAS supports two-factor authentication, adding an extra layer of security to user login. This requires users to provide a second verification factor, such as a code generated by a mobile app, in addition to their password.
    6. Antivirus and Antimalware: The NAS includes built-in antivirus and antimalware scanning capabilities. It can regularly scan files and folders for any potential threats, ensuring that the stored data remains secure and free from malware.
    7. Data Encryption: The NAS supports data encryption at rest, allowing administrators to encrypt the stored data. This ensures that even if the physical drives are stolen or accessed without authorization, the data remains encrypted and inaccessible.
    8. Network Segmentation: The NAS supports network segmentation, allowing administrators to create separate virtual LANs (VLANs) for different user groups or purposes. This helps in isolating sensitive data and restricting access within specific network segments.
    9. Audit Logs and Alerts: The NAS logs all user activities and provides audit logs for administrators to monitor and review. It can also generate real-time alerts for specific events or actions, such as failed login attempts or unauthorized access attempts.

    These features and mechanisms collectively ensure that the NAS TerraMaster F8-421 provides robust file access security, protecting data from unauthorized access, interception, and malware threats.

  • How does the NAS TerraMaster F8-421 implement user authentication and authorization to protect sensitive files from unauthorized access?

    The NAS TerraMaster F8-421 implements user authentication and authorization through a variety of methods to protect sensitive files from unauthorized access. Here are some of the key features:

    1. User Accounts: The NAS allows the creation of multiple user accounts with unique usernames and passwords. Each user has their own login credentials to access the system.
    2. User Groups: Users can be organized into groups, making it easier to manage permissions and access rights for multiple users simultaneously. Group permissions can be set to control access to specific files or folders.
    3. Access Control Lists (ACLs): The NAS supports ACLs, which provide fine-grained control over file and folder permissions. It allows administrators to define access rights for individual users or groups, including read, write, execute, or no access.
    4. Shared Folder Permissions: The NAS allows administrators to set permissions for shared folders. Permissions can be customized for each user or group, determining whether they can view, modify, or delete files within the shared folder.
    5. User Quotas: The NAS supports user quotas, which limit the amount of storage space each user can consume. This helps prevent users from monopolizing storage resources and ensures fair allocation.
    6. Two-Factor Authentication (2FA): The NAS supports 2FA, which adds an extra layer of security by requiring users to provide a second form of authentication, such as a verification code generated by a mobile app, in addition to their password.
    7. Secure Socket Layer (SSL) and Encryption: The NAS supports SSL/TLS encryption protocols, ensuring secure communication between the NAS and connected devices. It also offers data encryption options for sensitive files, protecting them from unauthorized access even if the physical storage devices are compromised.
    8. IP Access Control: Administrators can restrict access to the NAS based on IP addresses or IP ranges. This allows them to limit access to specific networks or devices, further enhancing security.

    By implementing these authentication and authorization mechanisms, the NAS TerraMaster F8-421 ensures that only authorized users can access sensitive files, and provides administrators with granular control over user permissions and access rights.

  • Can you explain the different levels of file access permissions and encryption options available in the NAS TerraMaster F8-421 to enhance data security?

    The NAS TerraMaster F8-421 provides various levels of file access permissions and encryption options to enhance data security. Here are the key features:

    1. User and Group Management: The NAS allows you to create multiple user accounts and groups with customizable access rights. You can assign specific permissions to each user or group, such as read-only, read-write, or no access, ensuring that only authorized individuals can access certain files or folders.
    2. Folder-Level Permissions: You can set permissions at the folder level, granting different access rights to different users or groups. This allows you to control who can view, modify, or delete specific folders and their contents.
    3. Shared Folder Encryption: The NAS supports shared folder encryption using the AES 256-bit encryption algorithm. This ensures that the data stored in the shared folders is encrypted and protected from unauthorized access. Encryption keys are required to decrypt the data, providing an additional layer of security.
    4. SSL/TLS Encryption: The NAS supports SSL/TLS encryption for secure data transmission over the network. This ensures that data transferred between the NAS and connected devices is encrypted, preventing eavesdropping and data interception.
    5. Two-Factor Authentication (2FA): The NAS supports two-factor authentication, which adds an extra layer of security to user login. With 2FA enabled, users need to provide a second form of authentication, such as a verification code from a mobile app, in addition to their username and password.
    6. IP Access Control: You can restrict access to the NAS by specifying IP address ranges or individual IP addresses that are allowed or denied access. This feature helps prevent unauthorized access from specific network locations.
    7. Data Snapshot and Backup: The NAS offers data snapshot and backup features, allowing you to create point-in-time snapshots of your data or schedule backups to external storage devices. These features help protect your data from accidental deletion, corruption, or ransomware attacks.

    By utilizing these file access permissions and encryption options, the TerraMaster F8-421 NAS enhances data security by controlling access, encrypting data, securing network transmissions, and providing additional authentication measures.