How to Resolve Data Loss Issues Caused by Oracle ASM Failures

Summary:  1. Fault description The ASM disk group is offline, and the ASM instance cannot be mounted. The ASM disk group consists of four 500G disks, the database and ASM software are 10.2.0.1, and the oracle database needs to be restored urgently. 2. Failure Analysis Analyze the disks that make up the ASM disk group, take out the ASM metadata, and analyze the metadata: the ASM storage metadata is damaged, so the disk group cannot be mounted.

1. Fault description The
ASM disk group is offline, and the ASM instance cannot be mounted. The ASM disk group consists of four 500G disks, the database and ASM software are 10.2.0.1, and the oracle database needs to be restored urgently.
2. Failure Analysis
Analyze the disks that make up the ASM disk group, take out the ASM metadata, and analyze the metadata: the ASM storage metadata is damaged, so the disk group cannot be mounted. Reorganize the ASM storage space, export the database files from the ASM disk group, and then detect and repair the database files. If the database file is intact, you can start the database using the database file exported from the ASM disk group. If the database files are damaged, the bottom layer parses these database files, imports the data into a new database, and restores the data.
3. Recovery process
1 Obtain ASM metadata at the bottom layer and reorganize the ASM storage space
2 Use the Beiya ASM parsing tool to parse the ASM structure and obtain the data files in ASM
Figure 1: 

3 Use the Beiya oracle file detection tool to detect the database files in the ASM disk group.
Figure 2: 

4 Use the North Asia oracle parsing tool to parse the data records in all data files and import them into the new database by user

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