NAS Synology DiskStation DS209+II / DS209+ / DS209 / DS209j RAID Arrays: Data Recovery Techniques After Natural Component Wear

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.

How can a NAS Synology DiskStation DS209+II / DS209+ / DS209 / DS209j device's network throughput or bandwidth capacity affect data transfer and potential loss?

The network throughput or bandwidth capacity of a NAS device like the Synology DiskStation DS209+II / DS209+ / DS209 / DS209j can have a significant impact on data transfer and potential loss. Here's how:

1. Data Transfer Speed: The network throughput determines how quickly data can be transferred between the NAS device and other devices on the network. A higher network throughput allows for faster data transfer, reducing the time required to backup, access, or transfer files. Conversely, a lower network throughput can result in slower data transfer speeds, leading to delays and inefficiencies.
2. Concurrent Connections: The bandwidth capacity of the NAS device affects the number of concurrent connections it can handle simultaneously. If the device has limited bandwidth capacity, it may struggle to handle multiple users accessing or transferring data simultaneously, leading to congestion and slower transfer speeds.
3. Potential Data Loss: Insufficient network throughput can increase the risk of data loss during transfer. When transferring large files or performing backups, if the network bandwidth is not sufficient, data packets may be dropped or corrupted, leading to incomplete or corrupted files. This can result in data loss or the need for retransmission, wasting time and resources.
4. Performance and User Experience: A NAS device with higher network throughput provides a better user experience, especially for tasks that require real-time access to data or streaming media. For example, streaming high-definition videos or accessing large files over a low-bandwidth connection may result in buffering or choppy playback.

To optimize data transfer and reduce potential loss, it is important to ensure that the NAS device's network throughput matches the requirements of the network and users. This can be achieved by:

• Using a wired Gigabit Ethernet connection: Wired connections generally provide higher bandwidth capacity compared to wireless connections, ensuring optimal data transfer speeds.
• Upgrading network infrastructure: If the existing network infrastructure is outdated or limited, upgrading to faster switches, routers, or network cables can improve network throughput.
• Load balancing: If the NAS device supports link aggregation or load balancing, combining multiple network interfaces can increase overall bandwidth capacity and distribute the load across multiple connections.
• Prioritizing network traffic: Configuring Quality of Service (QoS) settings on the NAS device or router can prioritize network traffic for critical applications, ensuring smooth data transfer even during high network usage.

By considering and optimizing the network throughput and bandwidth capacity of a NAS device, users can enhance data transfer speeds, reduce potential loss, and improve overall performance.

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

Although NAS DiskStation DS209+II / DS209+ / DS209 / DS209j 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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   How to Order Remote Data Recovery

Restoring data with Hetman RAID Recovery

This program recovers data from damaged RAID arrays and is fully compatible with Synology DiskStation DS209+II / DS209+ / DS209 / DS209j. 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 DS209+II / DS209+ / DS209 / DS209j has 2 HDD slots, and it supports the following array types:

• RAID 1;
• RAID 0;
• Basic;
• JBOD;

NAS supports:

• EXT3;
• FAT (External Disk Only);
• NTFS (External Disk 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 DS209+II / DS209+ / DS209 / DS209j 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