Recovering Data from NAS Synology DiskStation DS1517+ / DS1517 RAID Arrays: Challenges of Component Wear

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Synology DiskStation DS1517+ / DS1517
• 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 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.

How can data fragmentation impact data availability and potential loss on NAS Synology DiskStation DS1517+ / DS1517 devices?

Data fragmentation can impact data availability and potential loss on NAS Synology DiskStation DS1517+ / DS1517 devices in the following ways:

1. Reduced Performance: Fragmented data can lead to decreased read and write speeds on the NAS device. This can result in slower access to files and applications, affecting overall productivity and user experience.
2. Increased Disk Wear: Fragmented data requires more disk operations to retrieve or write files, leading to increased wear and tear on the hard drives. This can potentially shorten the lifespan of the drives and increase the risk of data loss due to hardware failure.
3. Data Loss Risk: Fragmentation can increase the risk of data loss, especially in cases where the file system becomes corrupted or files are overwritten due to fragmented blocks of data. If the file system is unable to locate all the fragments of a file, it may result in permanent data loss.
4. Difficulty in Data Recovery: Fragmented data can make data recovery more challenging in case of accidental deletion or drive failure. Fragmented files may be scattered across different areas of the disk, making it harder to retrieve the complete file.
5. Reduced Storage Efficiency: Fragmentation can also impact storage efficiency on the NAS device. Fragmented data takes up more space on the disks as it is stored in non-contiguous blocks. This can lead to wasted disk space and reduce the overall storage capacity available for other files and applications.

To mitigate these risks, it is recommended to regularly defragment the data on NAS Synology DiskStation DS1517+ / DS1517 devices. Defragmentation rearranges fragmented data blocks, optimizing disk performance, and reducing the chances of data loss. Additionally, implementing regular backups and RAID configurations can provide an extra layer of protection against data loss.

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

Although the NAS DiskStation DS1517+ / DS1517 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 Synology DiskStation DS1517+ / DS1517. 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 Synology

DiskStation DS1517+ / DS1517 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:

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 Synology DiskStation DS1517+ / DS1517 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