These are the slides from my FOWA workshop on how to scale your web apps.

1. Improving the
Performance of your
Web Application
Joe Stump, Lead Architect, Digg.com

2. Introductions

3. “Web 2.0 sucks (for scaling).”
Joe Stump, Lead Architect, Digg.com
Users want access to all of their crap at
all times. I, personally, don’t find your dog
funny or cute, but I’ll be damned if I’m
the one who’ll stand in the way of you
posting it and others consuming it.

4. Backend Considerations
Language considerations
Scaling out
Caching strategies
Content storage and delivery
Parallel data requests
Near time data processing
Partitioning data

5. Frontend Considerations
Reduce HTTP requests
Avoid inline JavaScript and CSS
Compression and Minification
Learn to love HTTP/1.1

6. “PHP doesn’t scale.”
Cal Henderson, Director of Development, Flickr.com
Languages don’t scale
Bytecode caching (PHP, Python, etc)
Robust library & driver support
Active developer communities

7. Discussion!
What language do you use?
Why?
Does it help you or hurt to use it?

8. Your mom lied; don’t share.
Decentralize data, storage, processing, etc.
Increased redundancy
Scaling becomes simple; add more boxes

9. Scaling Up

10. Scaling Up

11. Scaling Up

12. Scaling Out

13. Scaling Out

14. Scaling Out

15. Scaling Out

16. Scaling Out

17. Scaling Out

18. Scaling Out

19. Scaling Out

20. Scaling Out

21. Scaling Out

22. How do I scale easily?
1.Caching
2.Caching
3.Caching!

23. What are my options?
Disk based caching (e.g. Cache_Lite)
In memory caching (e.g. APC, Memcached)
Cloud caching (e.g. MogileFS, S3)

24. Disk based caching
Stupid simple
Cheap
Fairly easy to scale out
Dynamic images
Slower than others
Use fast disks!
RAM disks are faster

25. APC (PHP)
Bytecode caching
In memory user cache
Insanely fast
Not centralized or shared

26. Memcache
If you’re not using this you’re crazy
Easy to set up and use
Insanely fast over the network
Scales to insane heights
Failover, widely supported, etc.
Centralized and shared across site

27. Mogile FS
File and data store
Runs over WebDAV
Scales out infinitely (in theory)
Serialize data, store in file
Centralized and shared across site

28. Amazon S3
File and data store
Runs over HTTP
Scales out infinitely (in theory)
Serialize data, store in file
Centralized and shared across site
Costs money
Widely supported in all languages
Check out ThruDB

29. Discussion!
Are you using caching?
Why not?
If so, what’s your strategy?

30. Content Storage/Delivery
What are your storage needs?
Is it critical YOU store them?
How costly is it to store in-house?
Can you do it for free? (YAY! Mooching!)

31. i can has free storage?
YouTube for video
Scribd for documents
Flickr for images

32. Cloud Services (S3)
Simple to get up and running
No hardware maintenance
Costs money, but not as much as you think

33. NFS
Simple to set up and get running
Costs money, requires colocation, etc.
Does. Not. Scale.
Did I mention it doesn’t scale?
Stop gap solution at best

34. Mogile FS
Somewhat complicated to set up
Costs money, requires colocation, etc.
Scales exceptionally well
Used at Digg, LiveJournal, others
Check out File_Mogile by Digg (PEAR)

35. Roll Your Own
File storage IS your business
Highly specialized and customized
Costs money, requires colocation, etc.
Last resort

36. CDN
Completely outsource it
Costs a ton of money
Out of your control
Scales and scales and scales

37. Discussion!
What are you using for storage?
What’s worked for you?
What’s failed epically?

38. Parallel Data Requests
Access your data in parallel
Make data access asynchronous (WHAT?!)
Loosely couple your data access layer
All for the low, low price of FREE!*
*Offer only available for hardcore nerds looking for street cred.

39. HTTP
Parallel
Asynchronous
Non-blocking
Loosely coupled
Free foot massages!

41. HTTP

42. Gearman
Parallel
Asynchronous
Scales well

43. Discussion!
Which format to use for exchange?
Anyone doing this already?
Amazon, Google,Yahoo!

44. Near time processing
Does this need to be done NOW?
Offload to background processes
Offloading must be a no op
Feeds, Facebook, crawling, etc.

45. Cron
Run every minute or two
Simple
Great for batch jobs
Not decentralized, locking issues

46. Gearman
Fire and forget
Simple
Scales well
Digg Images
Nearly instant
Decentralized
No guarantees

47. Queues
Grid Engine by Sun
Starling by Twitter
Others?

48. Amzon’s EC2
http://open.blogs.nytimes.com/2007/11/01/self-service-prorated-super-computing-fun/
Near limitless computing resources
Remember; don’t share
Awesome for bots, crawling, etc.

49. Discussion!
What’s low(er) priority?
Where would you implement this?

50. Partitioning Data
Horizontal v.Vertical
Not all data lives in a single place
Hash records to partitions
App smart / logical sharding

51. Horizontal
192.168.0.1 192.168.0.2 192.168.0.3
Users Users Users
id int(11) id int(11) id int(11)
username char(15) username char(15) username char(15)
password char(15) password char(15) password char(15)
email char(45) email char(45) email char(45)

52. Hashing your data
oh hai! were’s mai dataz?!

53. How?
Put 10,000 users per partition
Partition users alphabetically
Partition home listings by zip code
Partition products by SKU

54. Vertical
192.168.0.1 192.168.0.2 192.168.0.3
Users UsersPrf UsersStg
id int(11) id int(11) id int(11)
username char(15) fname char(50) cmts_pg tinyint(2)
password char(15) lname char(50) cmts_lvl tinyint(1)
email char(45) url char(255) cmts_prf tinyint(1)

55. Why?
Avoid altering large tables
Save time during insert
Many small tables v. one large table
Lazy loading of rarely used data

56. Discussion!
Natural partitions in your data?
How would you hash your data?

57. Reduce HTTP Requests
Bundle JavaScript and CSS
Use sprites for images
Reduce images / outside objects

58. Reduce HTTP Requests
Bundle JavaScript and CSS
Use sprites for images
Reduce images / outside objects

59. Avoid inline JS/CSS
External = Cached
Inline = Not Cached

60. Compression / Minify
Enable Gzip compression sitewide
Use minification software on JS
jQuery/Prototype Minified

61. Learn to Love HTTP/1.1
Cache-Control: public/private
Connection: close
Expires: Thu, 28 Feb 2008 16:00:00 GMT

62. Conclusions
Share nothing, decentralize, redundancy
Caching, caching, caching, caching
Reduce, recycle and reuse

63. Resources
High Performance Web Sites
Essential Knowledge for Front-End Engineers
by Steve Souders
Serving JavaScript Fast
http://www.thinkvitamin.com/features/webapps/serving-javascript-fast
by Cal Henderson, Director of Development, Flickr.com

64. Questions?!

65. Contact/Flame Me
Joe Stump
joe@digg.com
http://joestump.net