some accident of storage loss of electricity lead oracle startup abnormity

 
 we meat some situation about of  loss of electricity  (such as storage  device and a motor room including   storage  device  and minicomputer ),

i find the result  of such things( loss of electricity  )  can lead oracle can't start , we use oracle 11g, and sometimes i can restart db after some action

and sometimes i can't restart db just recreate db,  our customer have a question such as  why oracle is so frangibility ?

i will show some example:all db is oracle 11g

1.our minicomputer is ok ,just   storage  device loss electricity, (this db have just one controlfile ) that alert.log report lgwr error ora-**,db is