[database data recovery] data recovery case of SQLSERVER database file missing for unknown reasons under Windows Server Environment

Database data recovery environment ：

5 block 2T The hard disk makes up RAID5, Divide LUN for windows Server usage ;

windows The server is equipped with Sql Server database ;

There are three logical partitions in the storage space with the sizes of ：500G、800G、2.3T.

Database failure ：

Database file missing for unknown reason , involves 5 Databases approx 6000 A watch , Unable to determine data storage location . The server is still powered on after the database file is lost , But it doesn't write a lot of data . The administrator shall contact the North Asia Data Recovery Center for data recovery .

Database fault detection ：

1、 Data recovery engineers use analysis to extract RAID Information and internal data block information reorganization RAID.

restructuring RAID

2、 extract LUN Internal three partition images .

3、 Scan the file system for missing files , Deleted database file not found , The database file is missing , Data cannot be recovered at the file system level .

Database data recovery process ：

1、 After detection, it is determined that the database file is missing and cannot be recovered , Data recovery engineers can only scan data pages , Extract the records in the page for data recovery .

2、 Use the data page scanner independently developed by the North Asia data recovery center to scan the data pages in the partition and extract . After scanning the images of the two partitions, it is found that the number of data pages in the partition of the system disk is very small and the data pages are seriously broken , A large number of data pages are scanned in another partition , Tentatively, this partition is the storage space for database files .

Scan data pages

3、 Reorganize system table .Sql Server The database uses system tables to manage all user tables , The system table records the number of columns in each table 、 Data type and constraint information . During parsing the system table, it is found that the system table in the extracted data page is damaged , Unable to read information normally . After the data recovery engineer communicates with the Administrator , It is known that there are backup files and the table structure has not been greatly changed after the backup , System tables are available .

4、 Restore backup .

Restore backup

5、 Extract the structure information of each table in the library .

Extract table structure information

6、 Parsing table structure scripts . Store the column information of each table in the database for subsequent use .

Scan script files

The table structure information is stored in the database

7、 Parse the system table to get the user table id Information 、 Association table structure and data page .（ To protect privacy , The following steps involve the table name of the user table and the data part in the data page ）

8、 New database , Use the software independently written by North Asia to parse the records and import them into the data recovery environment .

9、 Organize the recovery results . In addition to the database files, there are also several backup files in this partition , Duplicate data may exist after exporting records , It has to be heavy . Prepared by data recovery engineer SQL The stored procedure is de duplicated .

Database de duplication

10、 Validation data . After checking the data, the administrator said that there was no problem with the data , Hand over the data to the storage device prepared by the administrator , This data recovery is successful .