NAS Digiever DS-4125-RM Data Recovery: How to Handle RAID Array Challenges

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-4125-RM device's cache settings impact data loss risks?

The cache settings on a Digiever DS-4125-RM NAS device can impact data loss risks in the following ways:

1. Write Cache: The device's write cache is used to temporarily store data before it is written to the hard drives. If the write cache is enabled and data is only stored in the cache without being written to the hard drives, there is a risk of data loss in case of power failure or system crash. It is important to ensure that the write cache is properly flushed and data is safely written to the hard drives to minimize the risk of data loss.
2. Read Cache: The read cache stores frequently accessed data in memory for faster access. While the read cache can improve performance, it can also increase the risk of data loss if the cached data becomes corrupted or outdated. It is essential to regularly check and validate the integrity of the cached data to minimize the risk of data loss.
3. Cache Size: The size of the cache can impact data loss risks. If the cache size is too small, it may lead to frequent cache evictions, resulting in slower performance and increased disk I/O, which can increase the risk of data loss due to delays in writing or reading data. On the other hand, if the cache size is too large, it may increase the risk of data loss in case of power failure or system crash, as a larger amount of data needs to be written from the cache to the hard drives.
4. Cache Backup: Some NAS devices offer the option to back up the cache to a separate storage device or RAID array. This can provide an additional layer of protection against data loss in case of cache failure or corruption. Enabling cache backup can help minimize the risk of data loss by ensuring that the cached data is stored in a redundant and secure location.

Overall, it is important to carefully configure and monitor the cache settings on a Digiever DS-4125-RM NAS device to minimize the risk of data loss. Regular backups, proper cache flushing, and validation of cached data integrity are crucial steps to ensure data safety.

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

Although NAS DS-4125-RM 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-4125-RM. 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-4125-RM 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-4125-RM 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