How to Access Files on a RAID Disk When NAS Promise VTrak A3800fSL is Unreachable: Practical Steps

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 Promise 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 Promise VTrak A3800fSL devices?

RAID configurations in NAS Promise VTrak A3800fSL devices can have a significant impact on data loss. Here are a few ways RAID can affect data loss in these devices:

1. Redundancy: RAID configurations provide redundancy by distributing data across multiple disks. In case of a disk failure, the data can be recovered from the remaining disks. This reduces the risk of data loss due to hardware failures.
2. Fault tolerance: Different RAID levels offer varying degrees of fault tolerance. For example, RAID 1 and RAID 10 provide mirroring, where data is duplicated on multiple disks. If one disk fails, the data can still be accessed from the mirrored disk. RAID 5 and RAID 6 use parity information to reconstruct data in case of a single or double disk failure, respectively. These fault-tolerant configurations minimize the chances of data loss.
3. Hot spare: Some RAID configurations, such as RAID 5 and RAID 6, allow for the inclusion of a hot spare disk. A hot spare is an unused disk that automatically replaces a failed disk in the array. This reduces the downtime and the risk of data loss during the disk replacement process.
4. Rebuild process: When a failed disk is replaced in a RAID array, the data from the remaining disks is used to rebuild the data on the new disk. The rebuild process can be time-consuming, and during this time, there is a risk of data loss if another disk fails. RAID configurations with higher fault tolerance, such as RAID 6, can withstand multiple disk failures during the rebuild process without losing data.
5. RAID controller failure: In addition to disk failures, RAID configurations can also be impacted by the failure of the RAID controller. The RAID controller manages the array and ensures data integrity. If the RAID controller fails, it can result in data loss or the inability to access the data. Regular backups and redundancy in the RAID configuration can help mitigate this risk.

It is important to note that while RAID configurations can reduce the risk of data loss, they are not foolproof. Other factors such as human error, software issues, or multiple simultaneous disk failures can still lead to data loss. Regular backups and monitoring of the RAID array are essential to minimize the impact of data loss.

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

Although NAS VTrak A3800fSL 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 Promise VTrak A3800fSL. 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 Promise

VTrak A3800fSL has 24 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 1E;
• RAID 3;
• RAID 5;
• RAID 6;
• RAID 30;
• 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 Promise VTrak A3800fSL 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