the side plates 104 are vertically disposed on two opposite edges of the bottom plate 102 respectively the adapter board 110 is disposed between and vertical to the side plates 104 so as to divide the case 100 into a first space 106 and a second space 108 resulting in the first space 106 and the second space 108 disposed on two opposite sides of the adapter board 110 two sliding tracks not shown can be disposed on external sides of the two side plates 104 respectively for assembling the storage 10 onto a rack in which the first space 106 is located in a back side of the rack and the second space 108 is located in a front side of the rack the control board module 120 is disposed in the first space 106 and electrically connected to the adapter board 110 the control board module 120 comprises a first control board 122 and a second control board 124 redundantly with each other the first control board 122 and the second control board 124 are slidely disposed in the first space 106 parallel to the bottom plate 102 and vertically connected to the adapter board 110 when the storage 10 is assembled on the rack the first control board 122 or the second control board 124 can be hot plugged from the back side of the rack the power supply module 130 is disposed in the first space 106 and electrically connected with the adapter board 110 the power supply module 130 comprises a first power supply 132 and a second power supply 134 redundantly with each other in which the first power supply 132 and the second power supply 132 are slidely disposed in the.