TL;DR: Have a Dreamhost'd site? Please load test it with a simple GET for 50 concurrent users. Does it start off well and then spew 503 errors?
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We've got a client hosting a fairly basic web application on a respectably spec'd managed dedicated server at Dreamhost (12 cores, 260GB SSD, 16GB RAM). On any given week day, during school hours, there are 1.5-2k concurrent users using his product.
His customers (schools) depend on his web application (an educational product) being available every school day.
Recently teachers started reporting 503 Service Unavailable errors when multiple classes were using the web app, and they've been "forced" to have the students start using another product. This is of course very bad for business.
We've had some good conversations with Dreamhost Support, and they've dug into it a little, but they don't think it's an issue on their server or network, and we can't find any reason for our web application to be throwing the errors either.
We've done some simple, 50 concurrent user, load testing with a tool called Throng, and on loadimpact.com and we can easily reproduce the 503 issue in both tools. We also discovered that in addition to our site, we can reproduce it just as easily on another domain on a completely separated (shared) server.
With that last point in mind, it sure seems like a potentially Dreamhost-global (network?) issue. Maybe some kind of DDOS protection? You'd think that Support would know about something like that though.
So I was hoping you could please try and stress test your own Dreamhost'd domain(s), and let me know the result(s). I'm desperate to help our client, and an emergency Sunday night move to another company is starting to feel like our only option.
Thank you.
