RAID Array Recovery on NAS Thecus N2200PLUS: What to Do When It Stops Working

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 storage tiering or caching strategies impact data availability and potential loss on NAS Thecus N2200PLUS devices?

Storage tiering and caching strategies can have a significant impact on data availability and potential loss on NAS Thecus N2200PLUS devices. Here are a few ways these strategies can affect data:

1. Improved Performance: By implementing caching strategies, frequently accessed data can be stored in a faster cache, such as solid-state drives (SSDs). This improves read and write speeds, resulting in better overall performance. Faster access to data enhances data availability as users can retrieve information quickly.
2. Enhanced Data Redundancy: Storage tiering allows for the creation of redundant copies of data across different storage tiers. This redundancy ensures that even if one storage tier fails, the data remains available on another tier. This reduces the potential loss of data in case of hardware failures.
3. Increased Storage Capacity: Storage tiering enables the utilization of different storage media types, such as high-capacity hard disk drives (HDDs) and lower-capacity but faster SSDs. This combination allows for increased storage capacity while maintaining high-performance levels. More available storage capacity ensures data availability and reduces the risk of data loss due to insufficient space.
4. Data Protection: Some caching strategies include data protection mechanisms like write-back or write-through caching. Write-back caching temporarily stores data in the cache before writing it to the main storage. In case of power loss or system failure, the data in the cache can be lost. Write-through caching, on the other hand, writes data to both the cache and the main storage simultaneously, ensuring data availability and reducing the risk of data loss.

However, it's important to note that improper configuration or management of storage tiering and caching strategies can lead to potential data loss. For example, if the caching strategy is not adequately monitored or if the cache is not properly backed up, there is a risk of losing data stored in the cache. Therefore, it is crucial to implement these strategies carefully and regularly monitor their performance to ensure data availability and minimize potential loss.

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

Although NAS N2200PLUS 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 N2200PLUS. 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

N2200PLUS has 2 HDD slots, and it supports the following array types:

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 N2200PLUS 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