There is NO WAY a rackmount server will fit in a cabinet unless it is a very big cabinet ... they are about 28 inches long and designed specifically to be mounted in a rack (with mesh doors front and rear) with unimpeded airflow front to back.
Oh ... and they sound like a jet fighter with all the fans going.
Cheers.
EDIT: I suppose you could mount vertically, but these are still big, loud units.