By virtualization, I'm assuming you mean creating VPS' ?
32 gig is going to be too small for this if that's the case.
16 IP's might work, though if you can max that out, it'd be good.
It's a good thing to take a look at the cost of ipv4 with the provider, because, believe me, you'll need a ton IF you sell well.
Tom Whiting, WHMCS Guru
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