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

Contents

• Why Regular Data Recovery Tools Can’t Restore Files from RAID
• Key Information About the NAS Huawei OceanStor Pacific 9920
• How to Remove Hard Disks from Your NAS and Connect Them to a PC
  • Step-by-Step Data Recovery with Hetman RAID Recovery
  • How to Safely Recover Data from Disk Images
  • Where Are the User’s Files Actually Stored?
  • RAID Recovery Software: Detailed Comparison

Why Regular Data Recovery Tools Can’t Restore Files from RAID

Conventional hard drives store user data by writing it sequentially across the disk surface, which means an entire file is typically located on a single drive. In contrast, when data is written to a RAID array, each file is split into multiple fragments. These fragments are then distributed and written in sequence across all the drives in the array. Depending on the configuration, fragment sizes can range from 2 KB to 2 MB, so every file is physically stored across several disks at once.

This approach significantly increases read and write performance — after all, writing two halves of a 1 GB file to two drives simultaneously is much faster than writing the full 1 GB to a single disk. However, this same mechanism makes file recovery far more complex.

Different RAID levels use different methods to distribute and protect data. On top of that, manufacturers like Huawei often add their own proprietary structures and variations. As a result, data can be written to disks in many different formats, and each requires a specific approach during recovery.

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 Remove Hard Disks from Your NAS and Connect Them to a PC

Although the NAS OceanStor Pacific 9920 can be accessed over the network, you still need to remove its hard disks and connect them directly to a Windows PC. Only then can the recovery software properly scan and analyze the drives. Follow these steps:

1. Power off the NAS and disconnect it from the power source.

   WARNING! Before removing any drives, carefully read the device manual. Improper actions may damage both the NAS enclosure and the hard disks in the RAID array.

2. Remove the hard disks one by one, gently sliding each drive out of its slot. Remember that hard disks are highly sensitive: any impact or drop can cause serious physical damage.

3. Label each hard disk according to its position inside the NAS. The order of the drives is crucial for correct RAID reconstruction.

4. Connect the drives to your computer. In this video, we explain which ports you can use to connect hard disks and what to do if your PC does not have enough free connectors.

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   How to Order Remote Data Recovery

Step-by-Step Data Recovery with Hetman RAID Recovery

This program restores data from damaged RAID arrays and is fully compatible with Huawei OceanStor Pacific 9920. Each hard disk in the array contains technical metadata describing how files were written. When launched, Hetman RAID Recovery analyzes this metadata, automatically reconstructs the damaged array, and provides access to its contents. After that, you can browse the recovered disk and save your files. The program can also restore files that were accidentally deleted from the network drive.

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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;

How to Safely Recover Data from Disk Images

This utility allows you to create a complete copy of a disk and work with the disk image instead of the physical drive. This approach helps protect your data from:

• Overwriting during the recovery process;
• Additional data loss caused by bad sectors;
• User errors.

To create a disk image, follow these steps:

1. Ensure you have enough free space to store the image. Its size will typically match the size of the original disk.

2. In the main window, select the target disk and choose Tools - Save Disk. You can also select multiple disks if needed.

3. When the Image Creation Wizard opens, select whether you want to save the entire disk or only a specific region. Adjust the settings and click Next.

   

4. Choose the directory where the image will be saved. You may select any available disk connected to your PC or upload the image via FTP.

   

Where Are the User’s Files Actually 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.

RAID Recovery Software: Detailed Comparison