PRM-SCAN extract datafile from corrupted asm disk group

https://zcdn.parnassusdata.com/prmscan%20extract%20datafile%20from%20oracle%20asm%20diskgroup.mp4

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

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

corrupted asm diskgroup ,failed to mount
corrupted / formatted filesystem
deleted datafile from asm diskgroup
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 .