It might be noted that it is not only to keep it cool but to keep the humidity down. In cases such as electronics you can get too cold and cause condensation on parts being cooled.
A cooling unit too large may not run enough to remove humidity. This will call so much moisture as to create mold and mildew. One too small can make it too dry and not cool well during times where the electronics are producing the most heat.
We have a laser, Trumpf 5040, that is 6KW. The electronics in the boxes are kept at 86 F (30C). Each control box has it's own a/c. Those temps are suggested by Trumpf.
It is slightly different than a server but has pretty much the same cooling requirements.
