FIG. 1 is a top plan view of the stackable rack server in accordance with the claimed design;

FIG. 2 is a rear elevation view of the stackable rack server in accordance with the claimed design of FIG. 1;

FIG. 3 is a front elevation view of the stackable rack server in accordance with the claimed design of FIG. 1;

FIG. 4 left side elevation view of the stackable rack server in accordance with the claimed design of FIG. 1;

FIG. 5 is a right side elevation view of the stackable rack server in accordance with the claimed design of FIG. 1;

FIG. 6 is a bottom plan view of the stackable rack server in accordance with the claimed design of FIG. 1;

FIG. 7 is a top plan view of an alternative embodiment of the stackable rack server in accordance with the claimed design;

FIG. 8 is rear elevation view of the stackable rack server of FIG. 7;

FIG. 9 is front elevation view of the stackable rack server of FIG. 7;

FIG. 10 is left side elevation view of the stackabler rack server of FIG. 7;

FIG. 11 is right side elevation view of the stackable rack server of FIG. 7; and,

FIG. 12 is bottom plan view of the stackable rack server of FIG. 7.