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Comment by neya | Hacker News Reader

I disagree, this logic doesn't work always unless you have investor money lying around. For a bootstrapped business, it could mean living or dying. As an example, a client of mine was paying close to $5000 per month in server costs simply because of the scale of traffic they had on their site. By re-writing Wordpress in Elixir, I was able to bring their costs down to $1000 odd per month. It's actually cheaper than what any of their competitors are paying for, in servers as well.

This $4000 in savings actually allowed them to hire an additional full time developer to maintain their site. So, your logic only works for certain use cases, not all.

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Saying that you disagree and saying at the same time that you rewrote it in Elixir makes me think that wasn't a good use of the money. They will have problems hiring for it and it isn't even performant compared to other languages you could have written into if you really wanted to save money (i.e: golang).

Of course I don't have all the context, but, I cannot imagine any circumstance when rewriting some server side logic in elixir would be useful from a PoV of cost savings..

How do you know it wasn't a good use of the money? The client's site has been up for a year since then without any issues for 1/4th of the cost. Their investment in this stack wasn't much. Hiring wasn't a BIG problem, but it did take time. We used that savings to find a dev to maintain the site.

By RAW numbers, GoLang or something else maybe faster, for sure, but it will definitely extend the time to develop something like Wordpress because its frameworks I've tried (Eg. Gorilla) need more effort compared to using something like Phoenix that I use. Plus, a lot of devs were already onto Ruby, it's easier to onboard them into Elixir than GoLang.

> Of course I don't have all the context, but, I cannot imagine any circumstance when rewriting some server side logic in elixir would be useful from a PoV of cost savings..

I think you may not have worked with a high traffic site, just by swapping languages alone you get insane cost savings for that scale because it quickly adds up. Even if your new language is just 0.1 second faster per user, for a million users, it adds up really fast. As I mentioned, just by this switch alone we brought down the cost to 1/4th.

I believe GoLang or something else may have drastically reduced further, but it has the same downsides of Elixir (Harder to find talent for, learning curve). I'm a pure Elixir consultant, so I chose it. My client is more than happy with this outcome.

Yes, I kind of agree with everything you said actually! Apart from Elixir from a cost savings on infrastructure PoV, if that's how you wanted to frame it (since the context of the HN submission is about changing languages for better performance or not, and Elixir not being particularly fast).

How much did you charge to rewrite WordPress in elixir though?

And how big was the risk to have the invested time wasted? How long did you block new feature developement?

Safe to say they would've gone out of business if they kept burning that kind of money for the remainder of the year. This was around covid era, they didn't have a solid revenue stream from the traffic they got.

I'm obviously not going to reveal actual numbers, but it's safe to they spent less than what they would have spent being on Wordpress for the remainder of the year. Time to completion is 3 months. No new "feature" development was blocked. Remember - this is a content website (Wordpress is mostly used for content AFAIK and less for building features).

The moment it was done, we just switched nameservers. It had no impact on client's workflow or day to day life.

If it was a content website on Wordpress, couldn't Cloudflare's $5/mo APO have done the job? It static caches the site at the edge. You'd get almost a 100% hit rate unless there are strange requirements.

edit: Adding link with info about Cloudflare's APO product https://support.cloudflare.com/hc/en-us/articles/36004982231...

yes it could, but it's not webscale!

gotta use aws

Well to be fair he is an Elixir consultant so he rewrote it in Elixir.

APO is not a drop in to make what better, there are alot of kinks, and you could spend as much in dev time to get that working right. YMMV.

It can be a drop in (it was for my sites), but it depends on the requirements

Good suggestion, but if your content site is a news site, then homepage and certain category pages require by the second updates. Cloudflare unfortunately can't help and all the requests are directly hitting your database at that point. That forces you to get an expensive MySQL instance to sustain that kind of traffic.

Cloudflare will automatically purge the cache when you update or publish an article. Also from my understanding of APO, the cache will get distributed to all their edge locations without each one needing to hit the origin server. So if you update an article it would only get fetched a few times max until it gets updated again. That seems pretty good. Also as far as MySQL, you could install a Redis cache in front. Personally we use Varnish and Memcached as additional layers in front of Cloudflare (it works out of the box with Cloudways)

How much of that traffic could have been avoided by a CDN, a caching plugin, Varnish, and php-fpm?

You can't cache everything on a news website, especially the homepage. The homepage requires constant updates. For rest of the pages, I agree and I do use caching.

Even a one second cache would cap your homepage to 1 req/s which can be cheaply and trivially handled by any stack.

Every single large news website is cached.

This is some of the original thinking around StackOverflow, if I remember correctly from the podcasts. Jeff was a C# dev and using what was familiar, but he also commented on how you could get good performance out of some crappy code and easily refactor later.

Their whole culture elevated performance and they handled a lot of traffic with relatively small amounts of hardware that they documented. I've got some familiarity with a Rails app where the devs seemed astonished at some of the details in their blogs about running SO.

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