The only thing I can possibly imagine that a server can do with 16GB of swap is leaking garbage like a sieve and then getting the garbage swapped out. On an incredibly local basis, yes, this might be a better idea than not having swap, but as a generalized reason for servers to have swap it's terrible. If that's not what's happening I am all ears as to what the situation really is, but I'm sure it'll be something very unusual; in general if your server has even the slightest need for performance it can't use swap.