My HP T630 wouldn't fit in MOD10, 10" rack, so I made this Vesa 10cm side support for him.
MOD10: 1225275-modular-10-server-rack-mod10 by MandicReally
There's 3 options to print the support side to be attached to the rack, depending if the rack is in its regular or extended size, and one that fits both versions.
I printed 2 versions, one in PETG and another in ABS, in both cases with 3 wall, 4 top and bottom layers, 20% triangles infill. Tree supports were used.