How to Restore NAS Huawei OceanStor Pacific 9920 Data from a Faulty RAID Array

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 Huawei 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 the number of drives in a NAS Huawei OceanStor Pacific 9920 device's RAID array impact data recovery and potential loss?

The number of drives in a NAS Huawei OceanStor Pacific 9920 device's RAID array can impact data recovery and potential loss in the following ways:

1. Redundancy: RAID arrays are designed to provide redundancy by distributing data across multiple drives. The more drives in the array, the higher the level of redundancy. This means that if one or more drives fail, the data can still be recovered from the remaining drives. With a larger number of drives, the RAID array can tolerate multiple drive failures without losing data.
2. Performance: The number of drives in a RAID array can also affect its performance. In general, more drives in the array can provide higher read and write speeds, as data can be accessed from multiple drives simultaneously. This can be beneficial for applications that require high-performance data access.
3. Rebuild Time: When a drive fails in a RAID array, it needs to be replaced and the data on the failed drive needs to be rebuilt onto the new drive. The rebuild process involves redistributing data across the remaining drives in the array. With a larger number of drives, the rebuild process can take longer, increasing the risk of data loss if another drive fails during the rebuild.
4. Probability of Drive Failure: The more drives in a RAID array, the higher the probability of drive failure. This is because the failure rate of individual drives is cumulative. As a result, a larger number of drives in the array increases the risk of drive failures, which can impact data recovery and potentially lead to data loss.

It is important to choose the appropriate RAID level and number of drives based on the desired level of redundancy, performance requirements, and the criticality of the data being stored. Regular backups and monitoring of the RAID array's health are also crucial to mitigate the risk of data loss.

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

Although NAS OceanStor Pacific 9920 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.

   Go to view

   

   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 Huawei OceanStor Pacific 9920. 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.

Go to view

How to recover data from a Huawei

OceanStor Pacific 9920 has 12 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 Huawei OceanStor Pacific 9920 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