N6220/N6240 Electrical Requirements-Two Controller Nodes, With One 256-Gb Flash Cache Module Or One 512-Gb Flash Cache Or Flash Cache 2 Module Per Controller Node; N6220/N6240 Electrical Requirements-One Controller Node, With One 256-Gb Flash Cache Module Or One 512-Gb Flash Cache Or Flash Cache 2 Module, And One I/O Expansion Module; N6270 Electrical Requirements-Two Controller Nodes, With One 512-Gb Or One 1-Tb Flash Cache Or Flash Cache - IBM N6270 Hardware And Service Manual