How to Prevent Data Loss on NAS Thecus N4820U-S/R and Retrieve Files That Were Erased

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.

Can virtualization technologies impact data loss risks in NAS Thecus N4820U-S/R devices?

Yes, virtualization technologies can impact data loss risks in NAS Thecus N4820U-S/R devices.

Virtualization allows for the creation of virtual machines (VMs) that can run multiple operating systems and applications on a single physical server. By utilizing virtualization, users can isolate and separate different workloads, reducing the risk of data loss.

Here are a few ways virtualization technologies can impact data loss risks in NAS Thecus N4820U-S/R devices:

1. Improved backup and disaster recovery: Virtualization allows for easy backup and restoration of VMs. Users can take snapshots of the VMs, creating a point-in-time copy of the entire system. In case of data loss or system failure, these snapshots can be used to quickly restore the VMs to a previous state, minimizing downtime and data loss.
2. Enhanced data protection: Virtualization technologies often provide features like high availability and fault tolerance. These features ensure that if a physical server or storage device fails, the VMs can be automatically migrated to another server without interruption. This helps to protect against data loss caused by hardware failures.
3. Data redundancy and replication: Virtualization allows for the creation of redundant storage systems. By replicating data across multiple NAS devices or using RAID configurations, data redundancy can be achieved, reducing the risk of data loss. In case of a hardware failure, the replicated data can be used to restore the system.
4. Centralized management and monitoring: Virtualization technologies offer centralized management and monitoring tools. These tools provide a holistic view of the VMs and their associated storage devices, making it easier to identify and address any potential risks or issues that could lead to data loss.

While virtualization technologies can help mitigate data loss risks, it's important to note that they should be used in conjunction with other best practices, such as regular backups, secure access controls, and proper network security measures, to ensure comprehensive data protection.

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

Although NAS N4820U-S/R 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 N4820U-S/R. 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

N4820U-S/R 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 N4820U-S/R 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