How to recover data from Thecus N2520 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 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 data fragmentation impact the read and write speeds, and potential data loss on NAS Thecus N2520 devices?

Data fragmentation can have several impacts on read and write speeds, as well as potential data loss, on NAS Thecus N2520 devices:

1. Read and Write Speeds: When data is fragmented, it is scattered across different physical locations on the storage device. This can lead to slower read and write speeds as the device needs to access multiple locations to retrieve or store the fragmented data. The fragmented data may also result in increased seek times, which further slows down the read and write operations.
2. Disk Fragmentation: Data fragmentation can also lead to disk fragmentation, where files are stored in non-contiguous clusters on the disk. This can cause additional delays in accessing the data, as the disk heads need to move to different locations to read or write the fragmented files.
3. Data Loss: Fragmented data can increase the risk of data loss. If a file is fragmented and one of the fragments becomes corrupted or lost, it may render the entire file inaccessible. As the NAS device stores data across multiple drives, the chances of data loss increase if the fragmentation is not managed properly.
4. Increased Wear and Tear: Fragmentation can cause increased wear and tear on the storage device. As the device needs to perform additional read and write operations to access fragmented data, it can lead to increased stress on the drive, potentially reducing its lifespan.

To mitigate these impacts, it is important to regularly defragment the NAS device. Defragmentation rearranges the fragmented data and organizes it in a more contiguous manner, improving read and write speeds and reducing the risk of data loss. Thecus N2520 devices may have built-in defragmentation tools or support third-party defragmentation software that can be used to optimize the storage and reduce fragmentation. Regular backups of important data should also be maintained to mitigate the risk of data loss.

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

Although NAS N2520 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 N2520. 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

N2520 has 2 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• 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 N2520 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