1. Design Patterns for
Scalability
Concept Camp 2009
Hagerstown, MD
Chris Ballance
Microsoft Corporation
http://twitter.com/ballance

2. About me
•Started with a Commodore 64 at age 5
•ASP.NET and Sharepoint developer
•Enterprise content management
•Agile fanboy & ScrumMaster
•Transitioning from Volvo IT to Microsoft

3. "Scalability is hard"
-me

4. Designing for scalablity
•What changes?
•When to scale
•What are my SLA requirements?
•What is my budget?

5. When to optimize for scale?
•Well? When should you?

6. Start Small
•Design your system to run on a
single web server and separate db
•Consider whether to scale
verticaly, horizonally or both
•K.I.S.S.
•Be lazy
•Consider: Can this run in the
cloud?

7. Loose coupling
•Limits dependencies
•Promotes parallelism
•Limit "Single Points of Failure"
•Flexible
•Easier to change

8. Be Stateless
•Matches the HTTP Protocol
•Parallelism / FP advantages
•Encourages loose coupling
•Better for server farms
•Mobile device latency
considerations

9. Trim bloat
•Viewstate
•GZIP, minify, etc.
•Consolidate web resources
•Clean terse markup
•YSlow - FireBug plug-in

10. Flyweight
•Memory sharing
•Object re-use
•Factory pattern abstraction

11. Caching
•Benefits
•< resource usage(cpu, mem,
etc.)
•Faster response times
•Fewer DB hits
•Types
•Output caching
•Fragment caching
•Data caching

12. Prototype Pattern
•Object consistency
•Reuse objects with expensive Inits
•Polymorphism
•Flyweight alternative

13. Lazy Loading
•Right-sized data sets
•What you need, when you need it
•Pipeline optimization

14. Caching with Flyweight

15. Out of process caching
•Memcached
•Project Velocity
•IBM's "WebSphere eXtreme Scale"
•Oracle Coherence

16. Connection pooling
•Minimize TCP ports used
•Reduce round-trip
•Pipeline optimization

17. Offload specialized tasks
•Media streaming
•Large downloads
•Web Accelerators

18. Case Studies

19. Large manufacturing Co.
•Small Farm vs. High traffic
•Downtime causes $ loss
•3,000+ content editors globally
•Intranet, Extranet, & Internet facing
•Using SharePoint Publishing
•Highly customized platform

20. Twitter

21. Facebook

22. Sources
•Design patterns - performance - http://is.gd/3gUup
•Enhancing web application performance with caching -
http://is.gd/3gUFK
•StackOverflow Community
•Codinghorror.com