
- Why Regular Data Recovery Tools Can’t Restore Files from RAID
- Key Information About the NAS Synology DiskStation DS1520+
- 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 Synology 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.
Can the use of specific backup and recovery strategies help reduce potential data loss risks on NAS Synology DiskStation DS1520+ devices?
Yes, the use of specific backup and recovery strategies can help reduce potential data loss risks on NAS Synology DiskStation DS1520+ devices. Here are a few strategies that can be implemented:
- Regular backups: Implement a regular backup schedule to ensure that important data is backed up frequently. This can be done using built-in backup features of the Synology DiskStation, such as Snapshot Replication, Hyper Backup, or Time Machine.
- Offsite backups: Store backups in an offsite location to protect against physical damage or theft of the NAS device. This can be achieved by utilizing cloud backup services, remote replication to another Synology NAS, or by manually transferring backups to an external storage device kept offsite.
- RAID configuration: Configure the Synology DiskStation with a suitable RAID level to provide data redundancy. This will help protect against data loss in case of a hard drive failure. Common RAID configurations include RAID 1, RAID 5, or RAID 6.
- Multiple disk redundancy: The DS1520+ supports the use of an expansion unit, allowing for additional hard drives to be added. By utilizing multiple disk redundancy, such as RAID 6, data can be protected even if two drives fail simultaneously.
- Regular firmware updates: Keep the DiskStation's firmware up to date to ensure it has the latest security patches and bug fixes. This helps to minimize the risk of vulnerabilities that could be exploited by attackers.
- Disaster recovery plan: Develop a disaster recovery plan that outlines the steps to be taken in case of data loss or system failure. This plan should include details on how to restore data from backups, rebuild RAID arrays, and recover the system to a functional state.
By implementing these backup and recovery strategies, the risk of data loss on NAS Synology DiskStation DS1520+ devices can be significantly reduced.
How to Remove Hard Disks from Your NAS and Connect Them to a PC
Although the NAS DiskStation DS1520+ 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 Synology DiskStation DS1520+. 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 Synology
DiskStation DS1520+ has 5 HDD slots, and it supports the following array types:
- Synology Hybrid RAID (SHR);
- RAID 6;
- RAID 5;
- RAID 10;
- RAID 1;
- RAID 0;
- Basic;
- JBOD;
NAS supports:
- Btrfs;
- EXT4;
- EXT3 (External Disk Only);
- FAT32 (External Disk Only);
- exFAT (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 Synology DiskStation DS1520+ network-attached storage keeps DSM (DiskStation Manager) 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 |

