RAID Array Recovery on NAS QNAP TDS-h2489FU: What to Do After It Breaks

Has your NAS QNAP TDS-h2489FU 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?

RAID Array Recovery on NAS QNAP TDS-h2489FU: What to Do After It Breaks

QNAP TDS-h2489FU 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 TDS-h2489FU. We’ll walk through the most common causes of failure and demonstrate proven methods to restore files from a lost or degraded RAID array.

RAID Array Recovery on NAS QNAP TDS-h2489FU: What to Do After It Breaks

RAID Recovery™ 2.8
Recover data from damaged RAID arrays inaccessible from a computer.
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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 QNAP 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 the use of a UPS (Uninterruptible Power Supply) help minimize data loss risks during power outages or disruptions for NAS QNAP TDS-h2489FU devices?

Yes, the use of a UPS (Uninterruptible Power Supply) can help minimize data loss risks during power outages or disruptions for NAS QNAP TDS-h2489FU devices.

A UPS provides backup power to the NAS device in case of a power outage or disruption. It acts as a buffer between the main power source and the NAS, ensuring a continuous and uninterrupted power supply. This allows the NAS to properly shut down or continue operating on battery power until the main power is restored.

By using a UPS, you can prevent sudden power loss or fluctuations that could potentially damage the NAS or corrupt the data stored on it. It provides a safeguard against data loss, ensuring that the NAS has enough time to gracefully shut down or operate on battery power until the power is stable again.

It is important to select a UPS with sufficient capacity to handle the power requirements of the NAS and other connected devices. Additionally, configuring the NAS to automatically shut down or enter a low-power mode during extended power outages can further minimize the risk of data loss.

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

Although the NAS TDS-h2489FU 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 QNAP TDS-h2489FU. 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 QNAP

How to recover data from a QNAP

TDS-h2489FU has 24 HDD slots, and it supports the following array types:

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

NAS supports:

  • ZFS;
  • EXT4;
  • EXT3;
  • exFAT;
  • FAT32 (External Disk Only);
  • NTFS (External Disk Only);
  • HFS+ (External Disk Read Only);

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 QNAP TDS-h2489FU network-attached storage keeps QTS (QuTS hero) 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 TDS-h2489FU, feel free to leave a comment!
  • Gilbert Leggott
    Gilbert Leggott 14.09.2023 23:52 #
    Can data recovery from a NAS QNAP TDS-h2489FU device be performed if there are issues with the motherboard or system board?
    • Hetman Software
      Hetman Software 15.09.2023 00:59 #

      Yes, data recovery from a NAS QNAP TDS-h2489FU device can be performed even if there are issues with the motherboard or system board. In such cases, the data recovery process typically involves extracting the hard drives from the NAS device and connecting them to a separate computer or specialized data recovery equipment. By bypassing the faulty motherboard, it is possible to access the data stored on the hard drives and recover it. However, it is recommended to consult with a professional data recovery service provider for assistance in such situations to ensure the best chances of successful data recovery.

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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 is iSCSI and how does it work?

    iSCSI (Internet Small Computer System Interface) is a protocol that allows the transmission of SCSI (Small Computer System Interface) commands over IP networks, enabling the connection of storage devices over a network. It is a storage networking standard that facilitates the sharing, backup, and replication of data between servers and storage devices.

    iSCSI works by encapsulating SCSI commands within IP packets, which are then transmitted over TCP/IP networks. It utilizes the client-server model, where the iSCSI initiator (client) sends SCSI commands to the iSCSI target (server) to perform storage-related operations.

    Here's a simplified step-by-step process of how iSCSI works:

    1. Initiator and target discovery: The iSCSI initiator discovers available iSCSI targets on the network using the target's IP address or domain name.
    2. Session establishment: The initiator establishes a session with the target, which involves negotiating parameters such as authentication and security settings.
    3. Login: After the session is established, the initiator performs a login process to authenticate itself with the target. This ensures secure access to the storage resources.
    4. Command execution: Once the login is successful, the initiator can send SCSI commands to the target to perform various storage operations such as reading, writing, and deleting data.
    5. Data transfer: The target processes the received SCSI commands and performs the requested operations on the storage device. It then sends the data back to the initiator over the network.
    6. Logout and session termination: When the initiator no longer requires access to the target, it can initiate a logout process to terminate the session and release the resources.

    iSCSI allows for the utilization of existing IP networks to provide storage connectivity, eliminating the need for dedicated Fibre Channel infrastructure. It enables centralized storage management, improves storage utilization, and provides flexibility in scaling and managing storage resources.

  • How does iSCSI differ from other storage protocols?

    iSCSI (Internet Small Computer System Interface) is a storage protocol that allows block-level access to storage devices over a TCP/IP network. It differs from other storage protocols in the following ways:

    1. Network connectivity: iSCSI uses standard Ethernet networks to transport SCSI commands and data, whereas other storage protocols like Fibre Channel (FC) require dedicated Fibre Channel networks.
    2. Cost-effectiveness: iSCSI leverages existing Ethernet infrastructure, eliminating the need for expensive Fibre Channel switches and adapters. This makes it a more cost-effective solution for small and medium-sized businesses.
    3. Scalability: iSCSI can scale to accommodate thousands of devices, making it suitable for large-scale storage deployments. Fibre Channel, on the other hand, has limitations in terms of the number of devices it can support.
    4. Distance limitations: iSCSI allows storage devices to be located over long distances, as it utilizes IP networks. In contrast, Fibre Channel has distance limitations and requires specialized equipment for long-distance connections.
    5. Compatibility: iSCSI is compatible with existing IP-based infrastructure, including switches, routers, and firewalls. This makes it easier to integrate and manage within existing network environments.
    6. Performance: While Fibre Channel historically offered higher performance due to its dedicated infrastructure, advancements in Ethernet technology have closed the gap. Modern iSCSI implementations can provide comparable performance to Fibre Channel in many scenarios.

    Overall, iSCSI offers a more flexible, cost-effective, and scalable storage solution compared to other protocols like Fibre Channel. However, the choice of storage protocol depends on the specific requirements of the organization and the existing infrastructure.

  • Does the NAS QNAP TDS-h2489FU support iSCSI? If yes, what are the benefits and features it offers for iSCSI storage?

    Yes, the NAS QNAP TDS-h2489FU does support iSCSI. Here are some benefits and features it offers for iSCSI storage:

    1. High performance: The TDS-h2489FU is powered by dual Intel Xeon processors and supports up to 1TB of DDR4 ECC RDIMM memory. It is designed to deliver high-performance iSCSI storage, ensuring fast data transfer rates and low latency.
    2. Flexible storage expansion: The NAS supports both SAS and SATA drives, allowing you to mix and match different types of drives for your iSCSI storage. It also supports QNAP's expansion enclosures, enabling you to easily expand your storage capacity as your needs grow.
    3. Advanced features: The TDS-h2489FU offers advanced features for iSCSI storage, including thin provisioning, MPIO (Multipath Input/Output), and LUN mapping & masking. Thin provisioning allows you to allocate storage space on-demand, optimizing storage utilization. MPIO provides redundancy and load balancing for improved performance and reliability. LUN mapping & masking allows you to control access to specific LUNs (Logical Unit Numbers) for enhanced security.
    4. Snapshot and backup: The NAS supports snapshot technology, allowing you to take point-in-time snapshots of your iSCSI LUNs for data protection. It also offers a variety of backup options, including QNAP's own backup solutions like QNAP Snapshot Agent and QNAP Hybrid Backup Sync, as well as third-party backup software compatibility.
    5. Virtualization support: The TDS-h2489FU is VMware, Citrix, and Microsoft Hyper-V certified, making it an ideal choice for virtualization environments. It supports VAAI (vStorage APIs for Array Integration) and ODX (Offloaded Data Transfer), which offload storage operations from the hypervisor to the NAS, improving performance and efficiency.
    6. Security and data protection: The NAS provides comprehensive security features for iSCSI storage, including CHAP authentication, IP access control, and AES 256-bit volume-based encryption. It also supports RAID configurations for data redundancy and protection against drive failures.

    These are just some of the benefits and features that the NAS QNAP TDS-h2489FU offers for iSCSI storage.