
- Why Regular Data Recovery Tools Can’t Restore Files from RAID
- Key Information About the NAS Buffalo TeraStation WS5400D0804
- How to Remove Hard Disks from Your NAS and Connect Them to a PC
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 Buffalo 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 does a NAS Buffalo TeraStation WS5400D0804 device store and manage data?
The NAS Buffalo TeraStation WS5400D0804 device stores and manages data using a combination of hardware and software components. Here is a breakdown of how it works:
- Hard drives: The device comes with multiple hard drive bays where you can install hard drives. These hard drives can be configured in different RAID configurations (e.g., RAID 0, RAID 1, RAID 5, etc.) to provide data redundancy and performance.
- RAID controller: The device has a built-in RAID controller that manages the configuration and operation of the hard drives in the selected RAID level. It handles tasks like data striping, mirroring, and parity calculations.
- Network connectivity: The TeraStation device is connected to a network, typically through Ethernet, allowing it to communicate with other devices on the network. This enables file sharing and data access from multiple devices simultaneously.
- File system: The device uses a file system (e.g., NTFS, FAT, ext4) to organize and manage the data stored on the hard drives. The file system provides a hierarchical structure for files and folders, allowing users to easily navigate and access their data.
- Operating system and software: The TeraStation device runs an embedded operating system (such as Buffalo's proprietary firmware or a Linux-based OS) that provides the necessary functionality for data management. The firmware includes various software components like file sharing protocols (e.g., SMB, NFS), user authentication, access control, and data backup features.
- Data management features: The TeraStation device offers various data management features, including user and group management, access control lists (ACLs) for fine-grained permissions, remote access through VPN or web-based interfaces, scheduled backups, snapshotting, and RAID rebuild/recovery capabilities.
- Web-based management interface: Users can access the device's management interface through a web browser, allowing them to configure settings, monitor system status, and perform administrative tasks like creating shares, setting up backups, and managing user accounts.
Overall, the NAS Buffalo TeraStation WS5400D0804 device combines hardware components (hard drives, RAID controller) with software (operating system, file system, management software) to provide a reliable and efficient solution for storing and managing data in a networked environment.
How to Remove Hard Disks from Your NAS and Connect Them to a PC
Although the NAS TeraStation WS5400D0804 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:
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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.
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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.
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Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.
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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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Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with Buffalo TeraStation WS5400D0804. 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.
How to recover data from a Buffalo
TeraStation WS5400D0804 has 4 HDD slots, and it supports the following array types:
- RAID 0;
- RAID 1;
- RAID 5;
- RAID 6;
- JBOD;
NAS supports:
- exFAT, VFAT, FAT 12 / 16 / 32;
- NTFS / ReFS;
- APFS / HFS+;
- Ext2 / 3 / 4 / ReiserFS / XFS / UFS / ZFS / Btrfs;
- VMFS / HikvisionFS;
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:
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Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.
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In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.
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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.

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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 Buffalo TeraStation WS5400D0804 network-attached storage keeps Windows Storage Server 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 |


To rebuild the RAID on a Buffalo TeraStation WS5400D0804 NAS, follow these steps:
Note: It's recommended to have a backup of your data before attempting any RAID rebuild to avoid any potential data loss.