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Comment by mrb | Hacker News Reader

I have a very good excuse for NOT hosting my site on "a CDN": one CDN is a central point of failure. Instead I host it on 3 geographically redundant dumb servers from 3 different hosting providers (and all my DNS records resolve to 3 IPs.) As a result my site has had 100% uptime since its deployment years ago, despite many individual outages at these hosters. There has also been multiple occurrences where an entire swath of the web was down because of outage at $CDN, while my site was chugging along just fine.

I think the most likely outage I might encounter would be due to operator error, eg. accidentally pushing a bad web server config to my 3 servers.

More details: http://blog.zorinaq.com/release-of-hablog-and-new-design/

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I read your blog post and some of the comments, and I don't see how you can justify this claim:

> As a result my site has had 100% uptime since its deployment years ago

Assuming your individual hosts did go down occasionally, how do you know how many of your visitors waited 2 or 3 minutes for the browser to try the alternative IP?

If you have no service level requirements, you definitionally have 100% uptime.

You post doesn't seem to really be advocating not using a CDN, but running your own CDN. Many people don't have the time / budget / inclination to do this themselves.

Thanks, love the post! Your DNS method is fine for basic redundancy, but what about actual load balancing, for when 1 of the 3 servers gets hit hard?

Very interesting. I've read your article and saw you're relying on DNS pinning, a concept that I didn't know about. What happens if the first GET request from a browser resolves to an IP that happens to be down? Will it retry the other A record's IP?

You can do the same redundancy with CDNs. Most big sites use a multi-CDN solution, and balance traffic based on price and performance, with the added benefit of automatic failover if a CDN has issues.

I've never seen any multi-CDN setup that fully avoids central points of failures. For example Cloudflare requires making Cloudflare nameservers the authoritative servers for your domain name. Therefore if they have an outage (and if the records aren't cached at the client level,) then your website is going to be inaccessible.

Really? I can't imagine you HAVE to set your NS to Cloudflare, there has to be alternatives. I work for a CDN, the idea of requiring a customer to set us as their NS is crazy to me.

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