I added ocsp stapling to a new nginx based reverse proxy system at a shared hosting site. A few months later one of the sysadmins mentioned that it was now taking several minutes for nginx to restart and it was gradually getting slower.
Turns out whenever you restart nginx it fetches the ocsp information for each certificate one after the other. The system now had about 100-200 sites on it. I turned ocsp off and the problem was solved.
I still use it on Nginx systems that only have a couple of certs on though.
On large deployments, every bastion (internet-facing host that handles traffic) should gets its own caching resolver and a copy of the internet-facing zones, pushed by puppet/chef. Helps a bunch w/ DDoS if the shop is too custom for CloudFlare || similar.
I believe that nginx will do the caching with valid=300s.
"DNS" does not let the client set the record TTL, and "DNS" in this case would be a round-trip request to the Google DNS servers listed in the config snippet - precisely what it was suggested be avoided.