NAS QNAP HS-210 RAID Arrays: Recovering from Mechanical and Logical Failures Explained

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 QNAP 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 a NAS QNAP HS-210 device's caching policy impact data loss risks?

The caching policy of a NAS (Network Attached Storage) device like QNAP HS-210 can impact data loss risks in several ways:

1. Write caching: NAS devices often use write caching to improve performance. This means that when data is written to the NAS, it may first be stored in a cache before being written to the actual storage drives. While this improves performance, it also introduces a risk of data loss. If there is a power outage or system failure before the data is written from the cache to the drives, the data may be lost.
2. Read caching: NAS devices may also use read caching to speed up data access. Frequently accessed data is stored in a cache for faster retrieval. However, if the data being read is modified or deleted while it is in the cache, there is a risk of data inconsistency or loss.
3. RAID configuration: NAS devices often support RAID (Redundant Array of Independent Disks) configurations for data redundancy and protection against drive failures. The caching policy can impact how data is distributed across the drives in a RAID array. If the caching policy is not properly configured, it may increase the risk of data loss in the event of a drive failure.
4. Cache management: The management of the cache itself can impact data loss risks. If the cache is not regularly flushed or synchronized with the storage drives, there is a higher risk of data loss. Similarly, if the cache is not properly monitored or maintained, it may lead to issues that can result in data loss.

To mitigate the data loss risks associated with caching policies on a QNAP HS-210 or any NAS device, it is important to:

• Implement an appropriate backup strategy to regularly back up data from the NAS to an external storage or cloud-based solution.
• Ensure that the NAS device has a reliable power supply and backup power source to minimize the risk of data loss during power outages.
• Regularly monitor and maintain the NAS device, including checking cache synchronization, updating firmware, and addressing any potential issues promptly.
• Configure the caching policy based on the specific needs of the data and workload, considering the trade-off between performance and data protection.
• Use RAID configurations for data redundancy and implement appropriate RAID levels based on the desired level of data protection.

It is recommended to consult the manufacturer's documentation and seek expert advice to properly configure the caching policy and mitigate data loss risks specific to the QNAP HS-210 device.

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

Although NAS HS-210 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 QNAP HS-210. 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 QNAP

HS-210 has 2 HDD slots, and it supports the following array types:

• RAID 1;

NAS supports:

• ZFS;
• EXT4;
• EXT3;
• exFAT;
• FAT32 (External Disk Only);
• NTFS (External Disk Only);
• HFS+ (External Disk Read Only);

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 QNAP HS-210 network-attached storage keeps QTS (QuTS hero) 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