Shulou(Shulou.com)06/01 Report--

I. description of database failure

Today, I would like to share with you an Oracle database failure data recovery case. The database failure is characterized by the loss of the ASM disk group, and the ASM instance cannot be mount. The database administrator tried to repair the database without success, so he contacted the local data recovery company in Beijing to restore the database.

Second, database fault analysis method

The database data recovery engineer first analyzes the underlying disks and extracts the ASM metadata by analyzing the disks that make up the ASM disk group for further analysis. Through further analysis by the database engineer, it was found that the ASM storage metadata had been corrupted, which caused diskgroup to fail to mount. The database data recovery engineer then reorganizes the ASM storage space, exports the database files in the ASM disk group, and detects and recovers the exported database files. In this step, if the data file is found to be complete through detection, then in the next step of data recovery, you can directly use the database file to start the database, and if the database file is also damaged, then these underlying database files need to be parsed and restored.

III. Database data recovery process

The main results are as follows: 1 firstly, the underlying data is analyzed and extracted according to the above method, and the ASM metadata is obtained, and the ASM storage space is reorganized by using ASM source data.

2 after getting the ASM storage space, the next step of data recovery needs to use a North Asia ASM parsing tool for ASM structure parsing, or you can use other common ASM parsing work or self-made parsing scripts. The ultimate goal is to obtain the data files in ASM.

3 the following is the detection of the extracted database file, and the test result is as follows:

4 according to the above method, we parse the data records in all data files with the help of a self-designed oracle database parsing tool, and then import them into the new database by user, as shown in the following figure:

4. Oracle database data recovery is successful.

Through the reorganization of the ASM storage space, the underlying parsing of the ASM disk exports the recovered database files and then parses these database files in one step. When the data is imported into the new database by the user, the database data recovery engineer verifies the successfully restored data by spot checking the data table, and then notifies the customer to fully verify the data. The data recovery result is complete, and the Oracle database data recovery is successful this time.

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