There's no technical limit on the number of SANs. However, as you speculated, there is a practical limit. Our tests show that after about 40 SANs you start to get a performance impact. So that limits the number of domains per cert to ~20 (since we include 2 SANs per domain, root.com & *.root.com).
Answer to the free question: SNI + IPv6. Hopefully one more reason for people to adopt IPv6. And limited IPv4 space is a much bigger factor for us than the CA cost.
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There's no technical limit on the number of SANs. However, as you speculated, there is a practical limit. Our tests show that after about 40 SANs you start to get a performance impact. So that limits the number of domains per cert to ~20 (since we include 2 SANs per domain, root.com & *.root.com).
Answer to the free question: SNI + IPv6. Hopefully one more reason for people to adopt IPv6. And limited IPv4 space is a much bigger factor for us than the CA cost.
Will we still be able to pay a moderate fee (like today) and skip SNI?