
- Why Regular Data Recovery Tools Can’t Restore Files from RAID
- Key Information About the NAS Asustor DRIVESTOR 4
- 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 Asustor 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.
Are there any recommended practices for protecting NAS Asustor DRIVESTOR 4 devices against physical theft or unauthorized access that can lead to data loss?
Yes, there are several recommended practices for protecting NAS Asustor DRIVESTOR 4 devices against physical theft or unauthorized access:
- Physical security: Keep the device in a locked and secure location, such as a locked cabinet or a server room, to prevent physical theft.
- Strong passwords: Set strong and unique passwords for the administrator account and all user accounts. Avoid using default or easily guessable passwords.
- Two-factor authentication (2FA): Enable 2FA for additional security. This adds an extra layer of protection by requiring a second verification step, such as a code sent to your mobile device, in addition to the password.
- Firmware updates: Regularly update the firmware of your Asustor DRIVESTOR 4 device to ensure that you have the latest security patches and bug fixes.
- Network security: Secure your network by using a strong Wi-Fi password and enabling encryption (WPA2 or higher). Additionally, consider using a firewall and enabling network segmentation to isolate the NAS from the rest of your network.
- Disable unnecessary services: Disable any unnecessary services or features on the NAS to reduce the attack surface. Only enable the services you actually need.
- Backup your data: Regularly backup your data to an off-site location or to a cloud storage service. This will ensure that even if the NAS is stolen or compromised, your data remains safe.
- User access control: Implement proper user access control by assigning specific permissions and access rights to individual users. Restrict access to sensitive data to only those who need it.
- Enable audit logs: Enable and regularly review the audit logs on the NAS to detect any unauthorized access attempts or suspicious activities.
- Regularly monitor and update security measures: Stay vigilant and keep up-to-date with the latest security practices and recommendations. Regularly review and update your security measures to adapt to new threats and vulnerabilities.
By following these recommended practices, you can significantly enhance the security of your Asustor DRIVESTOR 4 device and protect it against physical theft or unauthorized access.
How to Remove Hard Disks from Your NAS and Connect Them to a PC
Although the NAS DRIVESTOR 4 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 Asustor DRIVESTOR 4. 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 Asustor
DRIVESTOR 4 has 4 HDD slots, and it supports the following array types:
- RAID 0;
- RAID 1;
- RAID 5;
- RAID 6;
- RAID 10;
- JBOD;
NAS supports:
- Ext2;
- Ext3;
- Ext4;
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 Asustor DRIVESTOR 4 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 |


Yes, data recovery can be performed on a NAS Asustor DRIVESTOR 4 device even if there are issues with the storage drive or media errors. However, it is important to note that data recovery can be a complex and time-consuming process, and there is no guarantee of success.
If there are issues with the storage drive, it is recommended to first try basic troubleshooting steps such as restarting the NAS device, checking the connections, and updating the firmware. If the issue persists, it may be necessary to contact Asustor support for further assistance.
If media errors are present, it can indicate possible data corruption or damage. In such cases, it is advisable to consult a professional data recovery service. They have specialized tools and expertise to recover data from damaged drives or media errors. It is important to avoid any further attempts to access or repair the drive, as it can potentially cause more damage and reduce the chances of successful recovery.