https://zcdn.parnassusdata.com/prmscan%20extract%20datafile%20from%20oracle%20asm%20diskgroup.mp4 PRM-SCAN extract datafile from corrupted asm disk group let 's go ! asmcmd lsdsk lsdg let corrupt the asm disk header by manual dd if=/dev/zero of=/dev/vdb1 bs=1024k count=10 conv=notrunc this will write zero to asm header 10M SQL> alter diskgroup data mount; alter diskgroup data mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15017: diskgroup "DATA" cannot be mounted ORA-15040: diskgroup is incomplete fail to mount the corrupted asm disk group ok use PRMSCAN to scan the failed asm diskgroup's disk this only require read-only permission it will take long time to scan , up to the disk size java -jar PRMScan.jar --outputsh o1.sh this command will output lots of dd command , help you extract datafiles blocks and merge them into datafiles let see it some datafiles may need to be ignored , find out your datafiles !! execute the shell will generate datafiles under your current directory ! if you have multiple db's system01.dbf store on same diskgroup , you may need to distinguish them by yourself, or you can call parnassusData service let's extract data from the datafile using prm !! prm scan can work on 1. corrupted asm diskgroup ,failed to mount 2. corrupted / formatted filesystem 3. deleted datafile from asm diskgroup 4. deleted datafile from filesystem filesystem(ntfs,ext 2/3/4,xfs whatever filesystem type) we provide prm scan as a product (bundle with prm) or a service . contact us service@parnassusdata.com !!