1. UbiStore: Ubiquitous and Opportunistic Backup Architecture. Feiselia Tan, Sebastien Ardon, Max Ott Presented by: Zainab Aljazzaf

2. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

3. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

4. Introduction.. To prevent data loss in case of malfunctioning or lost devices. To prevent data loss in case of malfunctioning or lost devices. Backup! Backup! Backup has to be done periodically and often manually  up to date? Backup has to be done periodically and often manually  up to date? Many of these devices have, or soon, will have wireless connectivity. Many of these devices have, or soon, will have wireless connectivity. Portable backup system

5. Mobile Computing Environments

6. Introduction Mobile devices (mobile telephones, personal audio players, PDA, laptop computers.. etc) are used in many locations and environments than desktop computers. Mobile devices (mobile telephones, personal audio players, PDA, laptop computers.. etc) are used in many locations and environments than desktop computers. Those devices continuously record user’s life artifacts. Those devices continuously record user’s life artifacts. Storage is mainly local to the device. Storage is mainly local to the device.

7. Mobile lost ! BACKUP …

8. Introduction.. SIM Card information backup machine Mobile backup cardUSB SIM card reader - Mobile Backup system: AT&T mobile backup service allow its subscribers to store, update and access their contact information from the Web. - Backup cards:

9. Introduction.. - Mobile backup system:

10. Introduction.. The data volume and associated network cost makes traditional backup to a backup server cost prohibitive for most consumers. The data volume and associated network cost makes traditional backup to a backup server cost prohibitive for most consumers. What is needed is an automatic and ideally operating cost free solution for mobile devices. What is needed is an automatic and ideally operating cost free solution for mobile devices. Use short-range and peer-to-peer communication capability. Use short-range and peer-to-peer communication capability. UbiStore: a backup architecture, where mobile devices backup their data over short-range, ad- hoc wireless links to other devices encountered as a result of user mobility. UbiStore: a backup architecture, where mobile devices backup their data over short-range, ad- hoc wireless links to other devices encountered as a result of user mobility.

11. UbiStore Mobile to mobile backup - Main idea: typical user mobility patterns will incur some repetitive encounters in the course of daily life (public transports, home/office) which can facilitate the recovery of data in case of a device failure.

12. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

13. Goals and constrains.. No need for 100% recovery. No need for 100% recovery. Fully decentralized architecture. Fully decentralized architecture. Only short-range, peer-to-peer communication. Only short-range, peer-to-peer communication. Maintain user’s privacy and data integrity. Maintain user’s privacy and data integrity. Maximize the incentive to participate. Maximize the incentive to participate.

14. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

15. The exponential increase of mobile device’s storage satisfy the user needs. The exponential increase of mobile device’s storage satisfy the user needs. The existence of free P2P communication (Blutooth) -> discovery mode. The existence of free P2P communication (Blutooth) -> discovery mode. Encounter of other devices during the day. Encounter of other devices during the day. Human activity is largely repetitive. Human activity is largely repetitive. A unique information can survive the loss. A unique information can survive the loss. UbiStore overviews : Assumptions..

16. UbiStore overviews : Evaluation criteria.. The recovery time: Time necessary to restore lost data. The recovery time: Time necessary to restore lost data. It is the most important parameter as it deals with direct user’s perception of the system’s performance. It is the most important parameter as it deals with direct user’s perception of the system’s performance. The space efficiency: Ratio between backup data and effective data. It is impacting the per-bit cost of the overall backup system. The space efficiency: Ratio between backup data and effective data. It is impacting the per-bit cost of the overall backup system. The communication efficiency: reflects the communication overhead of using several peer-to-peer communication links compared with centralized backup mechanism. The communication efficiency: reflects the communication overhead of using several peer-to-peer communication links compared with centralized backup mechanism. The paper present an initial evaluation of UbiStore using the recovery time criteria, for two different mobility models. The paper present an initial evaluation of UbiStore using the recovery time criteria, for two different mobility models.

17. UbiStore overviews : Model.. A node in UbiStore is a software agent executed on a user’s device, and assigned a data area to be backed up. A node in UbiStore is a software agent executed on a user’s device, and assigned a data area to be backed up. Encounter: the event of two nodes establishing communication in the view to exchange data. Encounter: the event of two nodes establishing communication in the view to exchange data. At any time, each node in UbiStore operates in one of the following two modes: At any time, each node in UbiStore operates in one of the following two modes: - Backup mode: a node keeps sending data blocks to other nodes while at the same time receiving and storing data from other nodes. - Backup mode: a node keeps sending data blocks to other nodes while at the same time receiving and storing data from other nodes. - Recovery mode: used after a device failure or a lost device, where a node will seek to recover its data from any node encountered. - Recovery mode: used after a device failure or a lost device, where a node will seek to recover its data from any node encountered.

18. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

19. Architecture Block: the elementary unit of storage in UbiStore. Block: the elementary unit of storage in UbiStore. Blocks are immutable: once generated, they cannot be modified. Blocks are immutable: once generated, they cannot be modified. Any block is assigned a globally unique identifier, associated with an owner. Any block is assigned a globally unique identifier, associated with an owner. Blocks are not forwarded from one node to another node, i.e. a node will only send its own blocks to another node. Blocks are not forwarded from one node to another node, i.e. a node will only send its own blocks to another node.

20. - Block generation process: Node Architecture..

21. - UbiStore node functional overview:

22. Node Architecture: Data manager Choosing which block to send: Choosing which block to send: Selecting blocks for deletion: blocks to be deleted are chosen from the tail of the queue (the blocks we are most likely to encounter again in the short term are dropped first). Selecting blocks for deletion: blocks to be deleted are chosen from the tail of the queue (the blocks we are most likely to encounter again in the short term are dropped first).

23. - Computing storage space offers: several strategies: Node Architecture.. Fixed size: a constant amount of storage space is advertised for each encounter. Fixed size: a constant amount of storage space is advertised for each encounter. Adaptive: the offered storage space is biased to favor frequently encountered nodes, with longer contact durations -> frequently encountered nodes are also likely to be frequently encountered when it is time to recover the data after a failure. Adaptive: the offered storage space is biased to favor frequently encountered nodes, with longer contact durations -> frequently encountered nodes are also likely to be frequently encountered when it is time to recover the data after a failure.

24. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

25. Evaluation: simulation mobility models The random waypoint model in which nodes evolve in a two-dimensional square field with their destination and speed determined randomly. The random waypoint model in which nodes evolve in a two-dimensional square field with their destination and speed determined randomly. This model is unrealistic and does not represent any actual human mobility pattern, we use it to (This will provide baseline). This model is unrealistic and does not represent any actual human mobility pattern, we use it to (This will provide baseline). Commuters traveling on a train : high level of correlation between node movements. Commuters traveling on a train : high level of correlation between node movements.

26. Evaluation: Simulation result.. - Recovery speed vs. time (Random waypoint model):

27. The variation: recovery ratio vs. time (ratio=5) The variation: recovery ratio vs. time (ratio=5) Evaluation: Simulation result..

28. - Train scenario vs. random waypoint: This supports the main idea of UbiStore that the repetitiveness of human mobility over large timescale will increase the speed of date recovery.

29. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

30. Related work OceanStore and PAST: provide a self-organizing file system storage infrastructure to applications. OceanStore and PAST: provide a self-organizing file system storage infrastructure to applications. PeerStore: is a backup system. Is not adapted to disconnected networks and opportunistic communication. PeerStore: is a backup system. Is not adapted to disconnected networks and opportunistic communication. Pastiche: buddy have similar set of files. Buddies only exchange data that is not common for both. Pastiche: buddy have similar set of files. Buddies only exchange data that is not common for both.

31. Table of contents: Introduction. Introduction. Goals and constrains. Goals and constrains. UbiStore overviews. UbiStore overviews. - Assumptions. - Assumptions. - Evaluation criteria. - Evaluation criteria. - Model. - Model. Node Architecture. Node Architecture. Evaluation. Evaluation. - Simulation mobility models. - Simulation mobility models. - Simulation result. - Simulation result. Related Work. Related Work. Conclusion. Conclusion.

32. Conclusion The paper has presented the concept and initial design of UbiStore. The paper has presented the concept and initial design of UbiStore. The main idea is to perform backup in other devices encountered by a mobile device over time. The main idea is to perform backup in other devices encountered by a mobile device over time. The paper presented an early performance evaluation which shows the benefit of exploiting repetitive patterns in human mobility. The paper presented an early performance evaluation which shows the benefit of exploiting repetitive patterns in human mobility.

33. Thank you..