NAS Synology DiskStation DS420+ / DS420j RAID Arrays: Data Recovery Approaches After Natural Component Wear

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Synology DiskStation DS420+ / DS420j
• 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.

Are there any specific factors to consider when choosing a NAS Synology DiskStation DS420+ / DS420j device to minimize data loss risks?

Yes, there are several factors to consider when choosing a NAS device like the Synology DiskStation DS420+ or DS420j to minimize data loss risks. Here are some key factors to consider:

1. Redundancy: Look for NAS devices that support RAID (Redundant Array of Independent Disks) configurations. RAID provides data redundancy by distributing data across multiple drives, ensuring that even if one drive fails, your data remains intact. Both DS420+ and DS420j support RAID configurations.
2. Drive compatibility: Ensure that the NAS device supports compatible hard drives. Check the manufacturer's specifications to see which drive models and capacities are recommended. Using compatible drives reduces the risk of compatibility issues and potential data loss.
3. Backup options: Choose a NAS device that offers various backup options. Look for features like scheduled backups, incremental backups, and support for remote backups to external devices or cloud storage. Having multiple backup options helps protect your data in case of hardware failure.
4. Data protection features: Consider NAS devices that offer built-in data protection features like data scrubbing, snapshotting, and data encryption. Data scrubbing helps detect and correct errors on the drives, while snapshots allow you to restore previous versions of files. Data encryption ensures that your data remains secure even if the drives are stolen.
5. Power protection: Consider using an uninterruptible power supply (UPS) to protect your NAS device from power surges or sudden power outages. A UPS provides temporary power during such events, giving you enough time to safely shut down the NAS and prevent data loss.
6. Regular maintenance and firmware updates: Ensure that you regularly update the NAS firmware and perform routine maintenance tasks recommended by the manufacturer. This helps ensure that your NAS device operates optimally and reduces the risk of potential vulnerabilities or data loss.
7. Off-site backup: Consider implementing an off-site backup strategy to further minimize data loss risks. This involves backing up your important data to a remote location, such as another NAS device located in a different physical location or using cloud storage services.

By considering these factors, you can choose a NAS device that provides sufficient data protection and minimizes the risk of data loss.

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

Although the NAS DiskStation DS420+ / DS420j 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 DS420+ / DS420j. 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 DS420+ / DS420j has 4 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 DS420+ / DS420j 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