How to recover data from Synology DiskStation DS3617xsII / DS3617xs NAS

Contents

• Why can’t ordinary software tools restore files from RAID?
• How to take hard disks out of the NAS and connect them to a PC?
  • Restoring data with Hetman RAID Recovery
  • Safe recovery from disk images
  • Where are user’s files stored?
  • Comparison of software for RAID recovery

Why can’t ordinary software tools restore files from RAID?

Conventional hard disks keep user’s data by writing it to their surface in a consecutive way, and this is how an entire file is stored on a single hard disk. However, when data is written to a RAID system, a file is divided into several parts. Then these parts are written consecutively to all hard disks within such array. The size of such parts may range from 2 KB to 2 MB, so each file is stored on several hard disks at the same time.

Such approach helps to speed up read and write operations, and it is evident that saving two parts of a file having the size of 1 GB to two hard disks simultaneously is much faster than saving the same 1 GB of data to one hard disk. However, this peculiarity makes file recovery more complicated.

Various RAID levels store information in different ways. Additionally, manufacturers like Synology also introduce some modifications to this process, and that is why data can be written to hard disk in a wide variety of ways.

Are there any known limitations or issues related to specific NAS Synology DiskStation DS3617xsII / DS3617xs device models that can lead to data loss?

There are no specific limitations or issues related to the Synology DiskStation DS3617xsII / DS3617xs device models that can directly lead to data loss. However, as with any storage device, there are certain factors that can contribute to potential data loss:

1. Hardware Failures: Although the DS3617xsII / DS3617xs models are designed with high-quality components, hardware failures can still occur. This includes issues with hard drives, power supply units, or other components. Regular backups and redundancy measures can help mitigate the risk of data loss in such cases.
2. Power Outages: Sudden power outages or fluctuations can cause data corruption or loss if the device is not properly protected. Using an uninterruptible power supply (UPS) can help prevent data loss due to power-related issues.
3. User Error: Accidental deletion or overwriting of files by users can lead to data loss. It is important to educate users about proper data management practices and implement access controls to minimize the risk of accidental data loss.
4. RAID Configuration: The DS3617xsII / DS3617xs models support various RAID configurations for data redundancy and protection. However, incorrect RAID setup or management can result in data loss. It is crucial to understand the RAID configuration and follow best practices for managing and maintaining it.
5. Firmware and Software Updates: While firmware and software updates often bring improvements and bug fixes, there is always a small risk of compatibility issues or unforeseen bugs that could potentially lead to data loss. It is recommended to keep the device's firmware and software up to date, but also to perform backups before any major updates.

To minimize the risk of data loss, it is advisable to regularly back up your data to an external location or cloud storage, implement a proper disaster recovery plan, and follow best practices for data management and device maintenance.

How to take hard disks out of the NAS and connect them to a PC?

Although NAS DiskStation DS3617xsII / DS3617xs can be accessed over the network, you still need to take the hard disks out of the storage device and connect them to a Windows computer. Only in this case will the software be able to scan them properly. Here is what you should do:

1. Turn off the storage and disconnect it from the power supply.

   WARNING! Before you start taking hard disks out of your NAS device, read the manual carefully. Incorrect actions may damage your network-attached storage and/or the hard disks within the RAID system.

2. Take the hard disks out of the NAS one by one, carefully removing them from their slots. Remember that the disks are extremely vulnerable: hitting or dropping them may result in serious physical damage.

3. Make sure to mark each hard disk in accordance with how they were installed inside the NAS.

4. Remove the hard disks and connect them to the computer. In this video, we have explored what ports are used to connect hard disks, and what to do if there are not enough ports or connectors.

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Restoring data with Hetman RAID Recovery

This program recovers data from damaged RAID arrays and is fully compatible with Synology DiskStation DS3617xsII / DS3617xs. The hard disks that make up the RAID contain technical information about the algorithm used to save files. When launched, Hetman RAID Recovery reads this information and puts the damaged array together. Then you can open the disk and save your files. Also, you can recover the files accidentally deleted from the network drive.

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How to recover data from a Synology

DiskStation DS3617xsII / DS3617xs has 12 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);

Safe recovery from disk images

This utility lets you save an entire copy of the disk to file and then work with this image instead of the actual disk. Such feature helps to protect data on the disk from:

• Overwriting during the recovery process;
• Loss resulting from bad sectors;
• User mistakes.

To create an image, do the following:

1. Make sure that you have enough free space to save the image. The image file size usually equals the disk size.

2. Select the disk in the main window, and choose from the menu Tools – Save Disk. You can select multiple disks to be saved.

3. When the image creation wizard starts, you can choose to save the entire disk or select only a part of it. Specify the parameters and click Next.

   

4. At this stage, you need to choose a directory where to save the image. Choose any disk connected to this PC, or save the image by FTP.

   

Where are user’s files stored?

The Synology DiskStation DS3617xsII / DS3617xs 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.

Comparison of software for RAID recovery