Recovering from Mechanical and Logical Failures in NAS QNAP TBS-464 RAID Arrays

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 the number of drives in a NAS QNAP TBS-464 device's RAID array impact data recovery and potential loss?

The number of drives in a NAS QNAP TBS-464 device's RAID array can impact data recovery and potential loss in the following ways:

1. Redundancy: RAID arrays are designed to provide redundancy by distributing data across multiple drives. The more drives in the array, the higher the level of redundancy. This means that even if one or more drives fail, the data can still be recovered from the remaining drives. With fewer drives in the array, the level of redundancy decreases, increasing the risk of data loss.
2. Fault tolerance: RAID arrays use various RAID levels (such as RAID 0, RAID 1, RAID 5, RAID 6, etc.) to provide different levels of fault tolerance. Each RAID level has a specific number of drives required to operate. If the number of drives in the array falls below the required minimum, the RAID array may become non-functional, leading to potential data loss.
3. Rebuilding process: When a drive fails in a RAID array, the array needs to rebuild the data onto a replacement drive. This process involves reading data from the remaining drives and reconstructing the data on the new drive. With more drives in the array, the rebuilding process can be faster and less resource-intensive. However, with fewer drives, the rebuilding process can take longer, increasing the risk of a second drive failure during the rebuild, which can result in complete data loss.
4. Performance: The number of drives in a RAID array can also impact its performance. With more drives, the array can distribute the workload across multiple drives, resulting in faster data access and transfer speeds. However, with fewer drives, the performance may be slower, affecting data recovery and overall system performance.

In summary, having a sufficient number of drives in a NAS QNAP TBS-464 device's RAID array is crucial for maintaining data integrity, ensuring fault tolerance, and minimizing the risk of data loss during drive failures.

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

Although NAS TBS-464 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 TBS-464. 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

TBS-464 has 4 HDD slots, and it supports the following array types:

• RAID 6;
• RAID 5;
• RAID 10;
• RAID 0;
• RAID 1;
• JBOD;

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 TBS-464 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