Talk by Martin Buhr, Founder of Loadzen.com at Devtank on the 31st of January about the importance of load testing your site as a startup, how http://loadzen.com was built and the lessons learned.

1. Preparing for... inclement
weather
Martin Buhr
@martinbuhr
http://loadzen.com

2. So...
WHO HERE HAS LOAD
TESTED THEIR APP?

3. For those that haven’t
(or don’t know)

4. Many people may tell you...

5. That these are your problem...
(etc)

6. And they really can cause
trouble...

7. We know, it happened to us:
Jive.ly

8. Day 1:
Launch

9. Day 2:
Sarky email to TechCrunch

10. Day 3:
#1 on TechCrunch UK

11. Day 3:
#1 on TechCrunch US

12. Day 3:
#1 on Digg

13. Shit.

14. So what happened?
To Jive.ly:
• Traffic exploded
• Sign-ups exploded
• In-bound links exploded
• Rankings shot up
• People were buzzing
• Free press!

15. So what really happened?

16. We lost users

17. They lost confidence

18. We lost opportunities

19. And it was expensive...

20. :-(

21. But that isn’t the general
case

22. You aren’t a C10K site

23. You’re not trying to piss off
Anonymous

24. You’re not on TechCrunch
(yet)

25. Remember these?
(etc)

26. They don’t matter... yet
But these guys do...

27. ANYONE THAT GENERATES
TRAFFIC THAT YOU DON’T
EXPECT BUT REALLY
WANT

28. You may ask yourself:
Why should I care?

29. Why should I care?
• Your database:
– Shared SQL server
– Unoptimised queries
– Unoptimised schemas
– Unnecessary requests

30. Why should I care?
• Your code:
– Nested nested loops
– Inefficient iterators
– Large in-memory objects
– About a million other bad practices and shortcuts

31. Why should I care?
• Your interface:
– Large images
– On the fly processing
– Slow JavaScript
– Slow web services

32. All of these are exposed and
get exponentially worse the
higher your traffic

33. For start-ups, inefficient
code is expensive

34. For developers, it’s just
embarrassing...

35. Which is why we load test
:-)

36. Oh yeah...
• Your users get your service
• You make the most from your opportunities
• Users spend more on responsive sites
• You improve your bottom line
And best of all:
• You become a better developer

37. Learnt that the hard way...

38. That got me thinking...
Can I build my own?

39. Yes I can...
And that became Loadzen
(let’s take a look...)

41. What is it?
• Load testing in the cloud
• Multi-scenario, weighted testing
• Real-time results
• Chrome plug-in
• Pay as you test

42. What’s it built in?
• Django (FCGI)
• MySQL
• Lighttpd
• RabbitMQ
• Pyro
• TornadIO
• SocketIO

43. What’s it really built in?

44. Python. Pure and Simple.

45. Look! A diagram!

47. And what did we learn?

48. Log everything
• Dynamic RPC is hard
• Black box code hurts, open up your systems
• When your site breaks (and it will) – you know
why

49. Real-time is awesome
• Event-based dev changes the way you think
• Queues make everything seem scalable
• But they introduce their own problems!
– Queue -> Socket -> Browser is a killer on your
system
– Flow control and timing can be issues

50. UI: Make it simple, stupid
• If your UI sucks, your code is useless
• It’s not someone else’s problem
• If it makes your users life easier, it’s worth it.
• Always think – can I make it simpler?

51. Always think scale
• Don’t build for it, but think about it
– Cache your interface
– Use a CDN
– Make requests quick: think async
– Make sure your database is fast
– Use the right tool for the job!

52. Pragmatism pays off
• Don’t pick tech because it’s hot
• Pick it because it solves your problem:
– Elegantly
– Efficiently
• Architect for extensibility
– You’ll deal with it sooner or later

53. Measure Everything.

54. Be inquisitive
• Talk to your users
• Love them (not too much!)
• They are the single most important thing to
your company, react.
– Even if you can’t fix it

55. And lastly...

56. make stuff, be awesome.
(that’s our motto, btw)