Practical RAID Array Tips for NAS Digiever DS-4236 UHD Data Restoration

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 RAID (Redundant Array of Independent Disks) configurations impact data loss in NAS Digiever DS-4236 UHD devices?

RAID configurations in NAS Digiever DS-4236 UHD devices can greatly impact data loss. Here are a few ways RAID can affect data loss in these devices:

1. Fault tolerance: RAID configurations provide redundancy by distributing data across multiple disks. In case of a disk failure, the data can still be accessed from the remaining disks. This fault tolerance helps minimize data loss as it allows for the reconstruction of the lost data.
2. Data protection: RAID configurations often include features like mirroring or parity, which help protect against data loss. Mirroring duplicates data across multiple disks, ensuring that even if one disk fails, the data is still available on another disk. Parity, on the other hand, calculates and stores additional information that can be used to reconstruct data in case of a disk failure.
3. Hot-swapping: Many RAID configurations support hot-swapping, which means that failed disks can be replaced without shutting down the system. This reduces the downtime and minimizes the risk of data loss during disk replacement.
4. Performance impact: Different RAID configurations have varying levels of performance impact. Some configurations, like RAID 0, offer better performance but no redundancy, which means a higher risk of data loss. On the other hand, more redundant configurations like RAID 5 or RAID 6 may have a lower performance impact but provide better data protection.

It's important to note that while RAID configurations can significantly reduce the risk of data loss, they are not foolproof. Other factors like power outages, natural disasters, or human errors can still lead to data loss. Therefore, it is recommended to have additional backup measures in place, such as regular offsite backups, to further safeguard your data.

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

Although NAS DS-4236 UHD 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-4236 UHD. 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-4236 UHD 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-4236 UHD 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