Data Recovery Best Practices for NAS Promise Pegasus2 R4 RAID Arrays

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 Pegasus2 R4 devices?

RAID configurations in NAS Promise Pegasus2 R4 devices can have a significant impact on data loss. Here are a few ways RAID configurations can affect data loss:

1. Redundancy: RAID configurations, such as RAID 1, RAID 5, or RAID 6, provide redundancy by distributing data across multiple disks. This redundancy helps protect against data loss in case of disk failure. If one disk fails, the data can be rebuilt or recovered from the remaining disks.
2. Fault tolerance: By using RAID configurations with parity data (such as RAID 5 or RAID 6), the NAS device can tolerate the failure of one or more disks without losing data. Parity data allows the system to rebuild the missing data from the remaining disks.
3. Hot spare: Some RAID configurations allow for the inclusion of a hot spare disk. A hot spare is a spare disk that is kept in the NAS device and can automatically replace a failed disk without manual intervention. This reduces the downtime and minimizes the risk of data loss.
4. Performance impact: Different RAID configurations have different performance characteristics. For example, RAID 0 offers improved performance but no redundancy, while RAID 5 or RAID 6 provide better redundancy but may have slightly lower performance due to parity calculations. Choosing the right RAID configuration based on your performance and redundancy requirements is crucial to avoid data loss.
5. Rebuild time: When a disk fails in a RAID configuration, the data from the failed disk needs to be rebuilt onto a replacement disk. The time it takes to rebuild the data depends on the size of the disks, the amount of data, and the RAID configuration. During the rebuild process, the system is vulnerable to additional disk failures, which could lead to data loss if not properly managed.

It is important to note that while RAID configurations can provide protection against disk failures and reduce the risk of data loss, they are not a substitute for regular backups. Having a comprehensive backup strategy is crucial to protect against other forms of data loss, such as accidental deletion, file corruption, or catastrophic events.

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

Although NAS Pegasus2 R4 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 Pegasus2 R4. 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

Pegasus2 R4 has 4 HDD slots, and it supports the following array types:

• RAID 0;
• RAID 1;
• RAID 1E;
• RAID 3;
• 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 Promise Pegasus2 R4 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