How to Avoid Data Loss on NAS D-Link DSN-2100-10 and Recover Deleted Files Quickly

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 D-Link 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 D-Link DSN-2100-10 device's caching policy impact data loss risks?

The caching policy of a NAS (Network Attached Storage) device like the D-Link DSN-2100-10 can impact data loss risks in the following ways:

1. Write Caching: Write caching is a feature that temporarily stores write operations in cache memory before writing them to the actual storage disks. While write caching can improve performance by reducing disk I/O, it also introduces a risk of data loss in case of a power outage or system failure. If the cached data has not been written to the disks, it can be lost. To mitigate this risk, the NAS device should have a battery backup unit (BBU) or a mechanism to flush the cache to disk during power loss.
2. Read Caching: Read caching involves storing frequently accessed data in cache memory to speed up subsequent read operations. While read caching generally doesn't pose a direct risk of data loss, it can impact data integrity if the cache becomes inconsistent with the actual data on the disks. This can occur if the NAS device experiences a sudden failure or if the cache is not properly synchronized with the underlying storage. To minimize this risk, the NAS device should have mechanisms to ensure cache consistency and data integrity.
3. RAID Configuration: The D-Link DSN-2100-10 supports various RAID (Redundant Array of Independent Disks) configurations for data redundancy and protection against disk failures. The choice of RAID level and configuration can impact data loss risks. For example, RAID 0 offers high performance but no data redundancy, meaning a single disk failure can result in data loss. On the other hand, RAID 1 or RAID 5 provide varying levels of data redundancy, reducing the risk of data loss in case of disk failures. It is crucial to choose an appropriate RAID configuration based on the desired balance between performance and data protection.

In summary, the caching policy of a NAS device like the D-Link DSN-2100-10 can impact data loss risks by introducing potential vulnerabilities during write caching, cache consistency, and RAID configuration. Proper configuration, including battery backup for write caching, cache consistency mechanisms, and appropriate RAID levels, can help mitigate these risks and ensure data integrity and protection.

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

Although NAS DSN-2100-10 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 D-Link DSN-2100-10. 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 D-Link

DSN-2100-10 has 8 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 5;
• RAID 6;
• RAID 10;
• 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 D-Link DSN-2100-10 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