
- Why Regular Data Recovery Tools Can’t Restore Files from RAID
- Key Information About the NAS QNAP TVS-873
- 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 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.
Are there any specific precautions to take while migrating data between NAS QNAP TVS-873 devices?
Yes, there are some precautions to take while migrating data between NAS QNAP TVS-873 devices. Here are a few important ones:
- Backup your data: Before starting the migration process, it is crucial to create a backup of all your important data. This ensures that even if something goes wrong during the migration, you still have a copy of your data.
- Check compatibility: Ensure that both the source and target QNAP TVS-873 devices are running compatible firmware versions. It is recommended to update the firmware to the latest version before starting the migration.
- Verify storage capacity: Make sure that the target QNAP TVS-873 device has enough storage capacity to accommodate all the data from the source device. Check the available storage space and plan accordingly.
- Network stability: Ensure that your network connection is stable and reliable during the migration process. Any interruptions or network issues can lead to data corruption or loss.
- Plan for downtime: Migrating data between NAS devices can take time, especially if you have a large amount of data. Plan for a maintenance window or downtime to perform the migration without any interruptions.
- Follow QNAP's migration guide: QNAP provides detailed migration guides for specific models. It is recommended to follow their official documentation and instructions for a smooth and successful migration process.
- Test after migration: Once the migration is complete, test the accessibility and functionality of your data on the new QNAP TVS-873 device. Ensure that all your files, applications, and services are working as expected.
By following these precautions, you can minimize the risk of data loss or corruption during the migration process.
How to Remove Hard Disks from Your NAS and Connect Them to a PC
Although the NAS TVS-873 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:
-
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.
-
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.
-
Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.
-
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
Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with QNAP TVS-873. 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 QNAP
TVS-873 has 8 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:
-
Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.
-
In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.
-
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.

-
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 QNAP TVS-873 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 |


Yes, data recovery from a QNAP TVS-873 device can be attempted even if the storage disks have bad sectors. However, the success of the recovery process will depend on the severity of the bad sectors and the condition of the disks.
If the bad sectors are isolated and only a few, there are higher chances of successful data recovery. In such cases, data recovery software or specialized tools can be used to bypass the bad sectors and retrieve the data from the remaining good sectors.
However, if the disks have a large number of bad sectors or if they are physically damaged, the recovery process becomes more challenging. In such cases, it is recommended to seek professional data recovery services from specialized companies who have the expertise and equipment to recover data from damaged disks.
It is important to note that attempting data recovery on your own, especially if the disks are physically damaged, can further worsen the situation and potentially result in permanent data loss. Therefore, it is advisable to consult with experts in data recovery to maximize the chances of successful recovery.