ORA-15029: disk 'string' is already mounted

admin

ORA-15029: disk 'string'is already mounted by this instance
Cause: An attempt was made to add to a diskgroup a disk thatwas already
mounted by the current instance as part of some (possibly other) diskgroup.
Action: Specifya different disk in the command. Note that not even the FORCE
option can be used to correct the situation until the diskgroup containing thedisk
becomes dismounted by this instance.