RAID Array Recovery Tips for NAS Digiever DS-4016 Devices

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 Digiever 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 quality of service (QoS) settings impact data transfer reliability on NAS Digiever DS-4016 devices?

Quality of Service (QoS) settings can impact data transfer reliability on NAS Digiever DS-4016 devices in the following ways:

1. Bandwidth Allocation: QoS settings allow you to allocate specific bandwidth limits to different applications or services. By prioritizing critical applications or services, you can ensure that they receive sufficient bandwidth for reliable data transfer. This prevents congestion and ensures smooth data flow.
2. Traffic Prioritization: QoS settings enable you to prioritize certain types of traffic over others. For example, you can prioritize video streaming or VoIP traffic over regular file transfers. By giving higher priority to time-sensitive traffic, you can reduce latency and maintain reliable data transfer.
3. Traffic Shaping: QoS settings also provide traffic shaping capabilities, allowing you to control the flow of data. You can set limits on upload and download speeds for different applications or services. By regulating the data transfer rates, you can prevent bottlenecks and ensure reliable data transfer for all users.
4. Packet Prioritization: QoS settings enable you to prioritize certain types of packets within a network. By assigning higher priority to packets related to critical applications or services, you can ensure their timely delivery and reduce the chances of data loss or corruption.
5. Error Correction: Some QoS settings include error correction mechanisms, such as forward error correction (FEC). These mechanisms can detect and correct errors in data packets during transmission, improving the reliability of data transfer and reducing the need for retransmissions.

Overall, by properly configuring QoS settings on NAS Digiever DS-4016 devices, you can optimize network resources, minimize congestion, reduce latency, and ensure reliable data transfer for critical applications or services.

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

Although NAS DS-4016 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 Digiever DS-4016. 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 Digiever

DS-4016 has 4 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• 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 Digiever DS-4016 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