
- Why Regular Data Recovery Tools Can’t Restore Files from RAID
- Key Information About the NAS Buffalo TeraStation WS5400DN0804W2
- 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 can the number of drives in a NAS Buffalo TeraStation WS5400DN0804W2 device's RAID array impact data recovery and potential loss?
The number of drives in a NAS Buffalo TeraStation WS5400DN0804W2 device's RAID array can have an impact on data recovery and potential loss in the following ways:
- Data Redundancy: RAID arrays provide data redundancy by distributing data across multiple drives. The more drives in the array, the higher the level of redundancy, which means a lower risk of data loss. For example, a RAID 5 array with more drives can withstand the failure of multiple drives and still maintain data integrity.
- Rebuild Time: When a drive fails in a RAID array, the data needs to be rebuilt onto a replacement drive. The larger the RAID array, the longer it takes to rebuild the data onto a new drive. During this rebuild process, there is a higher risk of another drive failing, which could result in data loss.
- Failure Probability: With more drives in a RAID array, the probability of at least one drive failing increases. Each drive has its own failure rate, and as the number of drives increases, so does the likelihood of a failure occurring. If multiple drives fail simultaneously or in close succession, it can result in data loss.
- RAID Level: The number of drives can also impact the RAID level used in the array. Different RAID levels offer varying levels of data protection and recovery options. For example, RAID 0 offers no redundancy and is more susceptible to data loss, while RAID 6 provides dual parity and can tolerate the failure of two drives.
In summary, having more drives in a NAS Buffalo TeraStation WS5400DN0804W2 device's RAID array generally increases data redundancy and protection against drive failures. However, it also increases the complexity of data recovery and the potential for data loss if multiple drives fail or the rebuild process encounters errors. It is essential to regularly back up data and ensure proper maintenance and monitoring of the RAID array to mitigate these risks.
How to Remove Hard Disks from Your NAS and Connect Them to a PC
Although the NAS TeraStation WS5400DN0804W2 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 WS5400DN0804W2. 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 WS5400DN0804W2 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 WS5400DN0804W2 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 |


Yes, data recovery from a NAS Buffalo TeraStation WS5400DN0804W2 device can still be possible even if the device is experiencing network congestion or bandwidth issues. In such cases, it is recommended to troubleshoot and resolve the network issues first to ensure a stable and reliable connection to the NAS device.
Once the network issues are resolved, data recovery can be attempted using various methods. One common approach is to connect directly to the NAS device using a computer or another device via Ethernet cable. This bypasses the network congestion and allows direct access to the data stored on the NAS.
If direct connection is not possible or does not resolve the issue, another option is to remove the hard drives from the NAS device and connect them to a computer using a compatible interface (e.g., SATA or USB). In this scenario, specialized data recovery software or services can be used to recover the data from the individual hard drives.
It is important to note that data recovery from a NAS device can be a complex process, and it is recommended to seek professional assistance from data recovery experts if the data is critical and valuable.