1. CollabDraw Real-time Collaborative Drawing Board Shishir Prasad Prashant Saxena Prakhar Panwaria

2. CollabDraw

3.  Goals High Scalability High Fault Tolerance Strong Consistency Offline Mode Overview Client

4.  Clients  Browser  HTML5 local store  Worker Servers  Drawing Board data store  Session Manager  Meta-data store Components

5. Session Manager Register Workflow

6. Session Manager Worker Servers Client A Start Session Server IP Preferred Servers Client B Start Session Server IP Workflow

7. Session Manager Worker Servers Client A getWorker() Server IP Preferred Servers Client B Server Failure

8. Session Manager Worker Servers Client A Preferred Servers Client B getWorker() Disconnected getWorker () Disconnected Server Failure

9. Session Manager Worker Servers Client A Preferred Servers Client B Disconnected Mode Server Failure

10. Session Manager Worker Servers Client A Preferred Servers Client B Disconnected Mode getWorker() Server IP getWorker() Server IP Server Failure

11.  Hybrid Consistency Strong  Between Preferred Servers : Strong Eventual  Rest : Eventual through anti-entropy protocol  High Availability migration  Worker Failure: Dynamic client migration Disconnected  Network Failure: Disconnected mode  Partition Tolerance replicated  Drawing Boards data replicated CAP

12. Demo

13. Evaluation

14. Evaluation  Average time for a paint brush event to appear on the canvas  Single machine: ~20 ms  2 machines: ~32ms  Average recovery time (in case of server failure)  Single machine: ~18 s (Server up time)  2 machines: ~2 s

15. Enhancements

16. Thanks!

18. Supplement

19. (1) Main Page

20. (2) Canvas Page

21. (3) Dashboard

22. Evaluation