IBM System Storage Subsystem DS5020 - Manual (Page 204)

Top view of non-IBM rack specifications dimensions
The vertical distance between mounting holes must consist of sets of three
holes spaced (from bottom to top) 15.9 mm (0.625 in.), 15.9 mm (0.625 in.), and
12.67 mm (0.5 in.) on center (making each three hole set of vertical hole
spacing 44.45 mm (1.75 in.) apart on center). The front and rear mounting
flanges in the rack or cabinet must be 719 mm (28.3 in.) apart and the internal
width bounded by the mounting flanges at least 494 mm (19.45 in.), for the IBM
Storage System or eServer
™ rails to fit in your rack or cabinet (see Figure 91).
nonibm_topview
Back, No Door
571 mm (22.50 in.)
Drawer Rail
Mounting Flanges
494 mm (19.45 in.)
Front, No Door
451 mm (17.46 in.)
494 mm (19.45 in.)
203 mm (8.0 in.)
719 mm (28.31 in.)
51 mm (2.01 in)
Figure 91. Top View of non-IBM Rack Specifications Dimensions
174 IBM System Storage DS5020 Storage Subsystem: Installation, User’s, and Maintenance Guide