How to Fix a Faulty RAID Array in NAS Idis DR-8516 and Recover Data

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 Idis 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 RAID (Redundant Array of Independent Disks) configurations impact data loss in NAS Idis DR-8516 devices?

RAID configurations can have a significant impact on data loss in NAS Idis DR-8516 devices. Here are a few ways RAID can affect data loss:

1. Redundancy: RAID configurations, such as RAID 1 (mirroring) or RAID 5 (striping with parity), provide redundancy by distributing data across multiple disks. If one disk fails, the data can still be accessed from the remaining disks. This redundancy helps to minimize data loss in case of disk failures.
2. Fault tolerance: RAID configurations offer fault tolerance, allowing the NAS device to continue functioning even if one or more disks fail. The system can rebuild the data from the remaining disks onto a replacement disk, reducing the risk of data loss during the recovery process.
3. Performance: RAID configurations can impact data loss indirectly by affecting system performance. For example, RAID 0 (striping without redundancy) offers improved performance by splitting data across multiple disks, but it does not provide any redundancy. If one disk fails in a RAID 0 configuration, all the data stored on that disk will be lost.
4. Rebuild time: When a disk fails in a RAID configuration, the system needs to rebuild the data onto a replacement disk. The rebuild time can be lengthy, especially for larger capacities or higher RAID levels. During this rebuild process, if another disk fails or encounters errors, it can lead to data loss or corruption.
5. RAID controller failure: The RAID controller in a NAS device manages the RAID configurations and disk operations. If the RAID controller fails, it can result in data loss or make it difficult to access the data stored on the disks.

It is important to choose the appropriate RAID configuration based on the desired level of redundancy, fault tolerance, and performance. Regular backups and monitoring of the RAID system are also crucial to mitigate the risk of data loss in NAS Idis DR-8516 devices.

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

Although NAS DR-8516 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 Idis DR-8516. 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 Idis

DR-8516 has 8 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 50;
• RAID 60;
• JBOD;

NAS supports:

• exFAT, VFAT, FAT 12 / 16 / 32;
• NTFS / ReFS;
• APFS / HFS+;
• Ext2 / 3 / 4 / ReiserFS / XFS / UFS / ZFS / Btrfs;
• VMFS / HikvisionFS;

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 Idis DR-8516 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