1. P2P Architecture for Self-* Atomic Memory Emmanuelle Anceaume Maria Gradinariu Vincent Gramoli Antonino Virgillito

2. ISPAN 05Vincent Gramoli Goal Architecture for Scalable Multi- Reader/Writer Distributed Shared Memory in P2P Systems

3. ISPAN 05Vincent Gramoli Roadmap Applications There is a solution for each problem Modular memory architecture Self-Healing mechanism Traversing mechanism Self-Adjusting mechanism Conclusion

4. ISPAN 05Vincent Gramoli Applications WebServices Groupware …w/o cost of maintenance of any centralized control

5. ISPAN 05Vincent Gramoli Peer-to-Peer (P2P) Dynamism Decentralized Unstructured Wide-Scale

6. ISPAN 05Vincent Gramoli Related Problems Data Availability Load

7. ISPAN 05Vincent Gramoli Related Problems Atomic Consistency Data Availability Load

8. ISPAN 05Vincent Gramoli Dedicated Solutions Atomic Consistency Data Availability Load Self-Healing

9. ISPAN 05Vincent Gramoli Dedicated Solutions Atomic Consistency Data Availability Load Self-HealingSelf-Adjusting

10. ISPAN 05Vincent Gramoli Dedicated Solutions Atomic Consistency Data Availability Load Dynamic Quorums* Self-HealingSelf-Adjusting * Quorums = Mutually intersecting sets

11. ISPAN 05Vincent Gramoli Modular Approach Dynamic Quorums Self-Healing Self-Adjusting Traversal Module Load Balancer Module Adjuster Module

12. ISPAN 05Vincent Gramoli Single Object Memory Atomicity is preserved under object composition. The memory is obtained by composition of all single object memories. Some nodes have a copy of the same object X: the object’s replicas. We refer to those replicas as the memory of object X.

13. ISPAN 05Vincent Gramoli Adjuster Module Architecture Traversal Module Load Balancer Module Operation Manager operationoperation-ack Client

14. ISPAN 05Vincent Gramoli Logical Overlay The object’s responsibility is a CAN torus-grid shared by replicas. Each replica is responsible for a part of a virtual domain space [0,1) x [0,1). If two zones are adjacent, their responsible are neighbors. Client operation operation-ack

15. ISPAN 05Vincent Gramoli Bootstrapping Process Initially, one replica possessed object X. This is the only responsible of X. Then X is replicated and responsibility is shared among replicas. Each replica is responsible for a part of a virtual domain space [0,1) x [0,1). If two zones are adjacent, their responsible are neighbors.

16. ISPAN 05Vincent Gramoli Self-Healing Overlay failed replica

17. ISPAN 05Vincent Gramoli Self-Healing Overlay Assuming eventual failure detection. A neighbor becomes responsible of the failed replica’s zone. The neighbor choice is made by CAN takeover mechanism.

18. ISPAN 05Vincent Gramoli Traversing Overlay Consultation quorum: set of replicas responsible of a whole line. Propagation quorum: set of replicas responsible of a whole column. Request receiver Every propagation quorum intersects every consultation quorum

19. ISPAN 05Vincent Gramoli Self-Adjusting Overlay overloaded replica

20. ISPAN 05Vincent Gramoli Self-Adjusting Overlay

21. ISPAN 05Vincent Gramoli Self-Adjusting Overlay

22. ISPAN 05Vincent Gramoli Self-Adjusting Overlay Active replication on a node outside the grid.

23. ISPAN 05Vincent Gramoli Self-Adjusting Overlay underloaded replica

24. ISPAN 05Vincent Gramoli Self-Adjusting Overlay Similar to the self- healing mechanism

25. ISPAN 05Vincent Gramoli Conclusion Our approach uses various concepts  P2P overlay  dynamic quorums  replica control Result  Multi-Reader/Writer DSM in P2P Systems  Only local information is necessary  Fault tolerance is guaranteed  Load is balanced  Operations are atomic Future work  Using mechanism theory for incentive strategy