Shulou(Shulou.com)06/02 Report--

Server data recovery case background:

-- the server raid disk array group is paralyzed. There are a total of three hard disks in the disk array. Currently, a hard disk lights up with a red alarm. The key data to be recovered is the database data in disk D. Due to the reboot of the server after the storage failure, the previously offline hard disk was brought back online and data synchronization was carried out. Fortunately, the computer was forced to shut down before the synchronization was completed.

Server data recovery process:-- the server data recovery engineer first made a read-only mirror backup of the three hard drives in the array, and found that all three hard drives in the server could be identified and read normally during the backup process. No bad path was found on the hard disk-- then the server data recovery engineer analyzed the finished image files in detail. Through the raid virtual reorganization and XOR check of the analyzed raid basic information, the backup mirror file is analyzed in detail, the raid structure is reorganized, and XOR verification is carried out, but because the administrator has carried out synchronous operation after the data damage, this operation will damage the data, so the result of XOR check is partially passed, indicating that the data is damaged. The server data recovery engineer further analyzed the RAID array and tried to extract data from a variety of hard drives offline, but the data extracted from each attempt was the same. First of all, we have to analyze and repair the dat files in the E partition in the hope that we can find the backup files for data recovery, but the result of data recovery is still file corruption. The data recovery engineer analyzes the aggregated dat fragments to verify the integrity of the dat data, and the underlying structure shows damage. Data recovery engineers have tried several methods to extract data, but all of them have failed. In order to recover the corrupted data, the only way to recover the original data of the server is to make a final attempt by splicing fragments. The server data recovery engineer scans the data pages of the free space of partition D and analyzes and aggregates all the scanned fragments one by one. After a simple verification of the integrity and validity of the aggregated file fragments, the data in the backup file is exported and recorded in the engineer's new database. Through the upper application to connect to the database to verify the availability of data, the database file can be loaded normally, the user account in the upper application software is normal, and the normal data query can be carried out. Summary of successful server data recovery cases:

During the recovery process, 2 backup files of SealLib databases were found on disk E. However, a small part of the page structure in the backup file data is damaged, and more continuous data fragments are found in the results of the D partition scan, and the fragments are available. Through the integration and splicing of D partition fragments and E partition backup files. The final repair of the parsed data can support the normal use of the whole application, and the upper application can query the database content normally.

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