Oracle : Ошибка ORA-15029

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

Попробовать перевести

Поискать эту ошибку на форуме