The Node.js Scalability Myth

Presentation given on 27.04.2012 at Roots conference in Bergen, Norway.

Transcript

1. The Node.js Scalability Myth Felix Geisendörfer 27.04.2012 at Roots Conference (Bergen, Norway)
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
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?
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