How to Handle a Faulty RAID Array Recovery in NAS Huawei OceanStor 6810

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 data fragmentation impact data availability and potential loss on NAS Huawei OceanStor 6810 devices?

Data fragmentation can have several impacts on data availability and potential loss on NAS Huawei OceanStor 6810 devices:

1. Reduced Performance: Data fragmentation can lead to reduced performance on the NAS device. When files are fragmented and scattered across different locations on the storage system, it takes more time for the system to retrieve and assemble the data. This can result in slower read and write speeds, affecting overall system performance.
2. Increased Storage Overhead: Fragmented data requires more storage space than contiguous data. As files are broken into smaller pieces and stored in different locations, the storage system needs to allocate additional space to accommodate the fragmented data. This can lead to increased storage overhead and reduced available capacity on the device.
3. Data Loss Risk: Fragmented data is more susceptible to data loss. If a single fragment of a file becomes corrupted or lost, the entire file may become inaccessible. Since fragmented data is spread across different locations, the failure of any one component can result in the loss of multiple files or parts of files, increasing the risk of data loss.
4. Difficult Data Recovery: In case of data loss or system failure, recovering fragmented data can be more challenging and time-consuming. The fragmented nature of the data makes it harder to locate and retrieve the necessary fragments to restore the complete file. This can prolong the recovery process and increase the chances of incomplete or unsuccessful data recovery.

To mitigate the impact of data fragmentation on data availability and potential loss, it is important to regularly defragment the storage system. Defragmentation consolidates fragmented data, rearranges files in contiguous blocks, and improves data access and availability. Additionally, implementing proper backup and disaster recovery strategies can help minimize the risk of data loss and facilitate faster recovery in case of system failures.

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

Although NAS OceanStor 6810 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 Huawei OceanStor 6810. 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 Huawei

OceanStor 6810 has 2688 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 6810 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