The Node.js Scalability Myth

Transcript

1. The Node.js Scalability Myth Felix Geisendörfer 26.04.2012 at MixIT Conference

   (Lyon, France)

2. (@)felixge(.de)

3. core contributor

4. transloadit.com (using node since v0.0.6)

5. History

6. Ryan Dahl starts the node project (first commit) Feb 16,

   2009

7. Discovered node.js (v0.0.6) ~June, 2009

8. None

9. Core Contributor & Module Author node-mysql node-formidable + 30 other

   modules

10. Isaac Schlueter starts the npm package manager (first commit) Sep

    29, 2009

11. Ryan’s talk at JSConf.EU gets people excited about node Nov

    7, 2009

12. (c) @substack Jan 30, 2012 Ryan appoints Isaac to lead

    node.js

13. Topic of this Talk

14. I need to build an über-scalable web service. It will

    be the next big thing!

15. Easy! I will use node.js and MongoDB!

16. Easy! I will use node.js and MongoDB!

17. Because node.js is “scalable”, right?

18. None

19. Audience?

20. Node.js?

21. Are you measuring app performance in production?

22. 1000 req / s

23. 100 req / s

24. 10 req / s

25. 10 requests / per second = 864000 requests / day

    10 req / s

26. The End?

27. I REALLY need to build an über-scalable web service!!11!1

28. Scalability

29. (c) @substack

30. The Node.js Scalability Myth • Threads don’t scale • Event

    loops do

31. The Node.js Scalability Myth • Threads don’t scale • Event

    loops do (Probably) not true in 2012 (Very likely) not relevant

32. More relevant • Understanding your tools • Using the right

    tool for the job

33. Node’s Concurrency Model

34. Node’s Concurrency Model 1 var http = require('http'); 2 3

    http.createServer(function(req, res) { 4 res.end('Hello World'); 5 }).listen(8080); server.js

35. Node’s Concurrency Model $ node server.js

36. Node’s Concurrency Model • Node loads server.js from disk ->

    v8 compiles & executes • listen() allocates and binds a file descriptor • Event Loops starts running

37. Node’s Concurrency Model 1 while (true) { 2 int r

    = select(nfds, readfds, writefds, errorfds, 0); 3 if (r === 0) { 4 continue; 5 } 6 7 // Figure out which fds had activity, accept() on server fds, read() on // connection fds, write() queued writes 8 } Abstracted by libuv Different on Windows

38. Node’s Concurrency Model • Cooperative multitasking • Low memory usage

    • Fast / efficient • Simple (compared to threads)

39. Vertical Scalability

40. Adding more resources to a single node

41. Vertical Scalability • CPU • GPUs • Memory • Disk

    • Network

42. CPU

43. CPU (v8) • V8 compiles JS to Assembly • Just-in-time

    compilation (JIT) • Does pretty well in those language benchmarks

44. Computers of the future will have hundreds of cores!

45. CPU • Node is single threaded (runs on a single

    CPU) • No shared memory

46. But ...

47. Does your problem require shared memory?

48. If yes: Don’t use node

49. And: Good Luck

50. If no: child_process.fork()

51. Redis / ZeroMQ are your friends

52. GPUs

53. GPUs • No support in node itself • node-cuda addon

    by Kashif Rasul

54. Memory

55. Memory • No hard memory limit on 64 bit (since

    node-0.6 / v8-3.7) • JS is a garbage collected language (avoid huge heaps) • Buffers do not count towards heap

56. Network

57. Network • Node’s concurrency model is optimized for networking •

    Good at fully saturating available network resources

58. Disk

59. Disk • Done in thread pool • Unfortunately along with

    DNS at this point • Throughput ok, but not ideal yet • sendfile() not working yet

60. Does node scale vertically?

61. Yeah, good enough

62. Horizontal Scalability

63. Adding more nodes to a system

64. Bad News

65. Node.js has no horizontal scaling features

66. Even worse

67. This s#@t is really hard

68. Problems • De-coupling / encapsulation • CAP Theorem • System

    Automation

69. ...

70. Good Luck

71. One tip

72. Monitor & Measure! • Collect: node-measured, statsd, ... • Analyze:

    Graphite, Librato Metrics, ... • Debug

73. So if node doesn’t have magic scaling, what is it

    good for?

74. <Live Coding>

75. tl;dr • Know your requirements • There are no silver

    bullets

76. Questions? Slides will be available at felixge.de

77. Thanks

78. Feedback