B+-tree : Increase MI


Disk1: 11 l 12       20 a 21 e 22 e 30 h 31    32 n 40 r 41 s 42
Disk2:  A    A         A      C       E         E    E
Disk3:  E    E  G      H      I                 L    L    M
Disk4:  N    N  P      R      R	                S    T    X    X



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