Avoiding Data Loss on NAS Thecus N4560 and Recovering Deleted Files: Insider Techniques

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 Thecus 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 quality of service (QoS) settings impact data transfer reliability on NAS Thecus N4560 devices?

Quality of Service (QoS) settings can have a significant impact on data transfer reliability on NAS Thecus N4560 devices. Here are a few ways QoS settings can affect data transfer reliability:

1. Bandwidth Allocation: QoS settings allow you to allocate bandwidth to different applications or services on your NAS. By prioritizing certain applications, such as file transfers, over others, you can ensure that data transfers receive sufficient bandwidth for reliable and uninterrupted transfers.
2. Traffic Prioritization: QoS settings enable you to prioritize specific types of traffic, such as FTP or SMB, over others. By giving higher priority to data transfer protocols, you can ensure that file transfers are not affected by other network activities, such as streaming or web browsing, which may consume bandwidth and cause interruptions.
3. Traffic Shaping: QoS settings also allow you to shape the traffic flow by setting limits on the maximum upload and download speeds for different applications or services. By properly configuring traffic shaping, you can prevent any single application from consuming excessive bandwidth, which can lead to dropped packets and reduced reliability during data transfers.
4. Buffer Management: QoS settings can help manage buffer sizes and buffer thresholds on the NAS device. By optimizing buffer settings, you can reduce latency and ensure a smooth and reliable data transfer experience. Proper buffer management can prevent issues like packet loss or delays, which can impact the reliability of data transfers.
5. Congestion Control: QoS settings help in managing network congestion by preventing network saturation. By setting appropriate congestion control mechanisms, such as traffic prioritization or traffic shaping, you can avoid network congestion, which can lead to packet loss and reduced reliability during data transfers.

It is important to note that configuring QoS settings requires a good understanding of your network environment and the specific requirements of your data transfers. Properly configuring QoS settings on Thecus N4560 devices can significantly enhance data transfer reliability and ensure a smooth and uninterrupted experience.

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

Although NAS N4560 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 Thecus N4560. 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 Thecus

N4560 has 4 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 10;
• JBOD;

NAS supports:

• EXT3;
• EXT4;
• XFS;

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 Thecus N4560 network-attached storage keeps OS Linux 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