Stack Overflow: The Architecture – 2016 Edition

http://nickcraver.com/blog/2016/02/17/stack-overflow-the-architecture-2016-edition/

by Nick-Craver • 10 years ago

328 29 10 years ago

nickcraver.com

charlieegan3• 10 years ago

Wish more sites/companies/employees published this sort of information - really interesting stuff.

Are there any other examples of big (largely) Windows stacks? Stack Exchange is the only one I've seen discussed.

dijit• 10 years ago

Most of the places that have highly scaled Windows infrastructure and highly fault tolerant architecture tend to be the kinds of places with very paranoid middle managers..

Source: I work at one.

lobster_johnson• 10 years ago

Todd Hoff's High Scalability [1] is a very nice blog to follow if you like this kind of information about real-world stacks. He's been writing it for years. (Caveat: It's a while since I followed it closely.)

[1] http://highscalability.com/

dikaiosune• 10 years ago

Stuff the Internet Says on Scalability is an excellent weekly article he does with plenty of great resources. Lots of stuff that's just reposted from HN, but also many pieces on real-world architectures that I never see on HN or /r/programming.

marinabercea• 10 years ago

Not at this level of detail, but in the event you don't know about the site, try http://stackshare.io/stacks . You can see the app stack for the included companies at the levels: Application & Data, Utilities, DevOps, Business Tools.

HillRat• 10 years ago

Match.com and PoF come to mind -- Match on the very large infrastructure side, PoF more along the lines of "punching above its weight."

UK-AL2• 10 years ago

There tons of big .net stacks, you just don't here about them in the startup world.

In the corporate world however....

codeulike• 10 years ago

They have 11 IIS servers but interestingly he says this:

What do we need to run Stack Overflow? That hasn’t changed much since 2013, but due to the optimizations and new hardware mentioned above, we’re down to needing only 1 web server. We have unintentionally tested this, successfully, a few times. To be clear: I’m saying it works. I’m not saying it’s a good idea. It’s fun though, every time.

btown• 10 years ago

I interpret this as: Page render latency probably degrades, but the site doesn't go down. Slower loads certainly have a monetary cost, making 11 machines worthwhile, but in a pinch at least they won't go fully offline if 10 die.

dyladan• 10 years ago

That is quite the pinch

seanp2k2• 10 years ago

Interesting to consider how some companies doing much less work on their machines than SO need clusters of hundreds of servers, meanwhile they can serve the 57th site by global traffic (according to Alexa) from one physical machine .

Sure there is other stuff backing that one, but the next time you hear someone talk about big clusters and hundreds or thousands of nodes, just take a moment to appreciate how much can be done with one rack of gear these days.

jldugger2• 10 years ago

To be fair, they cache the hell out of their content.

daxfohl• 10 years ago

Granted it's a machine with 768 GB RAM.

mschuster91• 10 years ago

Fun fact: some of those browsers have been open for over 18 months. We’re not sure why. Someone should go check if those developers are still alive.

How is that actually possible to keep a single TCP/IP connection open over 18 months?!

jewel• 10 years ago

Someone probably opened up a browser on a server to look something up and then left it running. With a static IP and battery backup, only a reboot is likely to take it down. The connection should be able to survive short outages due to a firewall restart or momentary problem upstream, especially if there's no NAT in between.

I'm using SSH's ControlMaster in persistent mode on my desktop at work. The connections stay open for as long as the desktop is up, which can be months at a time.

fweespeech• 10 years ago

Web crawler that investigates websockets.

caleblloyd• 10 years ago

"During peak, we have about 500,000 concurrent websocket connections open. That’s a lot of browsers. Fun fact: some of those browsers have been open for over 18 months. We’re not sure why. Someone should go check if those developers are still alive."

It's impressive that SO held the connection open for 18 months! That's some seriously good uptime for a process that manages a TCP connection.

ksec• 10 years ago

Strange, no wonder why some Browsers stats are stuck with old versions.

novaleaf• 10 years ago

i am betting those persistent connections are bots, but not sure what kind of software they'd use? PhantomJs crashes every 50 or so requests.

paulftw• 10 years ago

So it's 125 million SQL queries or 6 million page loads per machine per day.

It also seems like average query is 1.2ms - am I missing something?

eleitl• 10 years ago

Why the Windows stack though?

bnastic• 10 years ago

Because it clearly works for them?

augustl• 10 years ago

Jeff Atwood and Joel Spolsky have their roots in the Windows community, so they used what they were familiar with.

UK-AL2• 10 years ago

Why not? It appears to be working well.

Stack Overflow: The Architecture – 2016 Edition

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