What to Do When Your NAS Thecus N8900V RAID Array Fails: Recovery Guide

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 N8900V devices?

Quality of Service (QoS) settings can have a significant impact on data transfer reliability on NAS Thecus N8900V devices. Here's how:

1. Bandwidth Allocation: QoS settings allow you to prioritize bandwidth allocation for different types of traffic. By allocating sufficient bandwidth to data transfer, you ensure that it gets enough resources to operate reliably. Without QoS, other network activities like streaming or browsing may consume most of the bandwidth, leading to data transfer issues.
2. Traffic Prioritization: QoS settings enable you to prioritize data transfer traffic over other less critical network activities. This ensures that data transfer packets are given higher priority and are not delayed or dropped due to congestion. Prioritizing data transfer traffic enhances reliability by minimizing the chances of packet loss or latency.
3. Traffic Shaping: QoS settings allow you to shape the traffic flow, limiting the bandwidth for certain applications or users. By shaping the traffic, you can prevent any single application or user from overwhelming the network and affecting data transfer reliability. This ensures fair distribution of resources and avoids network congestion.
4. Packet Prioritization: QoS settings enable you to prioritize packets based on their importance. For example, you can prioritize TCP/IP packets over UDP packets or prioritize packets from specific applications or protocols. Prioritizing important packets ensures that they are delivered in a timely manner, reducing the chances of data transfer failures or errors.
5. Congestion Control: QoS settings help in controlling network congestion by managing the flow of data. When congestion occurs, QoS mechanisms can prioritize and manage traffic to prevent data transfer reliability issues. By intelligently managing congestion, QoS settings ensure that data transfer is not adversely affected, even during peak usage periods.

Overall, QoS settings on Thecus N8900V devices play a crucial role in optimizing network resources, prioritizing data transfer traffic, and ensuring reliable data transfer. By properly configuring and utilizing QoS settings, you can enhance the performance and reliability of data transfers on NAS devices.

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

Although NAS N8900V 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 N8900V. 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

N8900V has 8 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 50;
• RAID 60;
• 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 N8900V 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