ORA-16001: database already open for read

admin

ORA-16001: databasealready open for read-only access by another instance
Cause: The database has been opened for read-only access byanother instance,
and cannot be opened for read/write access by this instance.
Action: Thisinstance must be opened for read/write access, or all other instances
must first be shut down and reopened for read-only access.