[North Asia server data recovery] data recovery case of data loss caused by misoperation of Huawei oceanstor series servers

Time:2022-5-9

Server data recovery environment:
Huawei oceanstor series servers;
Md1200 disk cabinet, RAID5 disk array group, 50t capacity;
Linux operating system, 1 Lun; Two partitions: partition 1 is expanded through LVM, and partition 2 is formatted as XFS file system.

Fault:
The user’s misoperation of the server reinstallation system leads to the inaccessibility of the second partition in the original server and the loss of data in the server partition. The reason is unknown. The server administrator shall contact the North Asia Data Recovery Center for server data recovery.

Server data recovery process:
1. In order to prevent the original data of the server from being damaged by the data recovery operation of the server, the data recovery engineer of North Asia will mirror and back up all disks in the original server. After the backup, reinstall the original disk back into the original server, and connect the image disk to the special equipment for data recovery in North Asia for data recovery.
2. Beiya data recovery engineers use the mirror disk to analyze the disk order, stripe size and other information of raid;
3. Use the analyzed raid related information to virtually reorganize the raid structure;
4. Locate the starting location of the partition of the XFS file system; Verify the integrity and correctness of XFS file system;
5. Repair the super block structure of XFS file system;

[North Asia server data recovery] data recovery case of data loss caused by misoperation of Huawei oceanstor series servers
Repair completed superblock

6. Repair the lost nodes and directory entries in XFS file system;

[North Asia server data recovery] data recovery case of data loss caused by misoperation of Huawei oceanstor series servers
Repair completed root node

[North Asia server data recovery] data recovery case of data loss caused by misoperation of Huawei oceanstor series servers
Redo catalog entry

7. After the repair, the data recovery engineer of North Asia wrote a program to parse the XFS file system and extract the data.

Data recovery results:
After analyzing the XFS file system of the server, the data recovery engineer of North Asia found that the super block of the file system header was lost, some directory entries of the file system were lost, and some old nodes were lost. According to the super block backup and the directory tree structure in the file system, the North Asia data recovery engineer repairs and restores the super block. After repairing and reconstructing the lost nodes and directory items, the data in the file system can be completely restored.

[North Asia server data recovery] data recovery case of data loss caused by misoperation of Huawei oceanstor series servers
Repair completed directory structure

Data security tips:
After the data is lost, do not do any destructive operation of writing to the storage to avoid damaging the data.

[North Asia server data recovery] data recovery case of data loss caused by misoperation of Huawei oceanstor series servers