Steps to Restore a NAS Buffalo Drive Station HD-CX500U2 RAID Array with Multiple Disk Failures

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Buffalo Drive Station HD-CX500U2
• How to Remove Hard Disks from Your NAS and Connect Them to a PC
  • Step-by-Step Data Recovery with Hetman RAID Recovery
  • How to Safely Recover Data from Disk Images
  • Where Are the User’s Files Actually Stored?
  • RAID Recovery Software: Detailed Comparison

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.

What are the common causes of data loss in NAS Buffalo Drive Station HD-CX500U2 devices?

There are several common causes of data loss in NAS Buffalo Drive Station HD-CX500U2 devices. These include:

1. Hardware failure: The hard drive inside the NAS device can fail due to various reasons such as mechanical issues, electrical problems, or manufacturing defects. This can result in data loss if the drive becomes inaccessible or unreadable.
2. Power surges or outages: Sudden power surges or power outages can cause damage to the NAS device and the connected hard drive. It can lead to data corruption or even complete loss of data if the drive gets damaged.
3. Accidental deletion: Users may accidentally delete important files or folders from the NAS device, resulting in data loss. This can happen due to human error or mistakenly deleting files thinking they are no longer needed.
4. File system corruption: The file system of the NAS device can get corrupted due to various reasons like improper shutdowns, software bugs, or malware infections. This can make the data stored on the device inaccessible or unreadable.
5. Virus or malware attacks: NAS devices are not immune to virus or malware attacks. If the device gets infected, it can lead to data loss or data corruption. The malware can delete or modify files, making them unusable.
6. Physical damage: Physical damage to the NAS device, such as dropping it or exposing it to extreme temperatures or water, can result in data loss. The hard drive inside can get damaged, leading to data inaccessibility.
7. Firmware or software issues: Problems with the firmware or software of the NAS device can cause data loss. This can happen due to software bugs, compatibility issues, or failed firmware updates.

It is important to regularly backup your data to minimize the risk of data loss and consider implementing data recovery solutions to recover lost data in case of any unforeseen circumstances.

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

Although the NAS Drive Station HD-CX500U2 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.

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   How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with Buffalo Drive Station HD-CX500U2. 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.

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How to recover data from a Buffalo

Drive Station HD-CX500U2 has 1 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• 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:

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.

   

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.

   

Where Are the User’s Files Actually Stored?

The Buffalo Drive Station HD-CX500U2 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