NAS Digiever DS-16316-RM Pro+ Data Recovery: Best Practices for RAID Array Recovery

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 a NAS Digiever DS-16316-RM Pro+ device's caching policy impact data loss risks?

The caching policy of a NAS (Network Attached Storage) device like the Digiever DS-16316-RM Pro+ can impact data loss risks in the following ways:

1. Write caching: NAS devices often use write caching to improve performance by temporarily storing write operations in cache memory before committing them to the underlying storage disks. While write caching enhances performance, it also introduces a risk of data loss in the event of a power failure or system crash. If the data is only stored in cache and not yet written to the disks, it may be lost. To mitigate this risk, NAS devices typically employ mechanisms like battery backup units (BBUs) or uninterruptible power supplies (UPS) to ensure that cached data is safely written to disk during power failures.
2. Read caching: Read caching is another technique used by NAS devices to accelerate data retrieval. It involves storing frequently accessed data in cache memory, allowing subsequent read requests to be served faster. However, if the cached data becomes corrupted or lost due to a hardware failure or other reasons, there is a risk of data loss. Therefore, it is important to regularly back up the data stored on the NAS device to protect against such potential losses.
3. Cache management: The caching policy and management settings of a NAS device can also impact data loss risks. For example, if the caching policy is set to prioritize performance over data integrity, there may be a higher risk of data loss in case of a system failure. On the other hand, if the caching policy emphasizes data integrity over performance, it may result in slower performance but reduce the risk of data loss. It is crucial to configure the caching policy based on the specific needs and requirements of the data being stored on the NAS device.

Overall, while caching policies can enhance performance, they introduce potential risks of data loss. It is essential to implement appropriate measures like power backup solutions, regular backups, and careful cache management to minimize these risks and ensure data integrity and availability.

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

Although NAS DS-16316-RM Pro+ 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-16316-RM Pro+. 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-16316-RM Pro+ has 16 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 Digiever DS-16316-RM Pro+ 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