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Virtual machine environment description

The virtual machine hardware environment is a brand 720 server, 4 2T STAT hard drives are equipped with a H710P raid card to form a raid10 disk array. The operating system is Xen Server version 6.2, Windows Server 2003 system. The upper layer is the Web server, and the website architecture is ASP + SQL 2005. There are two virtual disks, one is the data disk 5G space, the other is the system disk 10G space. A power outage in the computer room caused a VPS in the Xen Server server to be unavailable and the Xen Server virtual machine disk files were lost.

Virtual machine fault detection process

Prepare enough data space and fully back up the customer data to the North Asia data recovery environment server. After analyzing the disks in the server, it is found that the disks in the server are stored in the structure of LVM. In this form, each virtual disk is a lv, the virtual disk is in reduced mode, and Xen Server records the relevant information of lvm.

Find the / etc/lvm/backup/frombtye.com directory, query the relevant information of lvm, and there is no damaged virtual disk information. The lvm information must have been updated. You can only try to query the lvm information that has not been updated by analyzing the underlying layer. The query result is as follows (unupdated lvm information found at the bottom)

The engineer found the data area of the virtual disk, but the data has been corrupted. Therefore, the ultimate reason for the unavailability of the virtual machine is the loss of operating system and data caused by the destruction of the virtual disk.

Data recovery scenario 1:

As the storage law of the RAR compressed package file is the name of the file in the first sector of the file, you can usually extract the start location of the data according to the structure of the RAR compressed package, and then match the file name of the backup database compressed package with the file name of the existing compressed package location to locate the starting location of the database compressed package, and then restore the data to the area of the compressed package.

The data recovery process is very smooth, the engineer will recover the RAR format file for decompression, but the error "rar compressed file underlying corruption". Use the RAR repair tool to ignore errors to extract some data and query files, except for some website codes, there are no database backup files available. PlanA failed.

Data recovery scenario II:

In the database structure, the library name of the database is usually recorded on page 9, and the database page number and file number are recorded in each page. So you can go to the starting position of the underlying analysis database through the database structure, and then scan the data fragments that match the database page to reorganize the mdf file at the bottom. (after the mdf file is rebuilt, you need to check whether the file is complete by the mdf check program. Finally, the database engineer builds a new database environment and appends the data to the environment. Screenshots of the implementation process are as follows:

Data recovery result

Through the way of spelling database fragments, the database is successfully restored, and there is no problem after customer verification, and the whole data is restored successfully.

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