In data center terminology, server dimensions are depicted in rack units, that is, the form factors (width, height, and depth per unit) are standardized and servers are classified as 1U, 2U, and so on, to reflect the dimensions of the specific make and model. Here is a pictorial representation of an actual server node that we use in our setup to build the VSAN cluster; Dell PowerEdge R720xd is a 2U server:

Server hardware used as a VSAN node