NAS Synology DiskStation DS1621xs+ / DS1621+ RAID Arrays: Recovering Data After Wear and Tear of Components

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Synology DiskStation DS1621xs+ / DS1621+
• 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.

What is a NAS Synology DiskStation DS1621xs+ / DS1621+ (Network Attached Storage) device?

The Synology DiskStation DS1621xs+ and DS1621+ are network-attached storage (NAS) devices manufactured by Synology Inc. NAS devices are essentially storage servers that are connected to a network, allowing multiple users to access and share files over a local area network (LAN) or the internet.

The DS1621xs+ and DS1621+ models are designed for professional users and small to medium-sized businesses. They offer high-performance storage solutions with advanced features and scalability options.

Key features of the DS1621xs+ and DS1621+ include:

1. Hardware: These models are equipped with a powerful CPU, high-speed memory, and multiple drive bays for installing hard drives or solid-state drives (SSDs). They also have built-in redundancy features like hot-swappable drive bays and dual power supplies.
2. Storage Capacity: The DS1621xs+ and DS1621+ can support up to six 3.5-inch or 2.5-inch SATA hard drives or SSDs, providing a large storage capacity. Additionally, they offer options for expanding the storage capacity by connecting external expansion units.
3. Performance: These devices are designed to deliver high-speed data transfer rates, enabling fast file access and sharing. They support various RAID configurations for data protection and improved performance.
4. Software: Synology NAS devices come with DiskStation Manager (DSM) operating system, which offers a user-friendly interface for managing the storage, configuring settings, and installing applications. DSM provides a wide range of features like file sharing, data backup, multimedia streaming, cloud synchronization, and more.
5. Scalability: The DS1621xs+ and DS1621+ can be expanded by connecting additional expansion units, allowing users to increase their storage capacity as their needs grow. They also support various applications and add-ons from Synology's Package Center.

Overall, the Synology DiskStation DS1621xs+ and DS1621+ are robust NAS devices that provide reliable and high-performance storage solutions for businesses and professional users.

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

Although the NAS DiskStation DS1621xs+ / DS1621+ 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 DS1621xs+ / DS1621+. 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 DS1621xs+ / DS1621+ has 6 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 DS1621xs+ / DS1621+ 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