UbiStore: Ubiquitous and UbiStore: Ubiquitous and Opportunistic Backup Opportunistic Backup

Architecture.Architecture.

Feiselia Tan, Sebastien Ardon, Max OttFeiselia Tan, Sebastien Ardon, Max Ott

Presented by: Presented by: Zainab AljazzafZainab Aljazzaf

Table of contents: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.

Table of contents: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.

Introduction ..Introduction .. To prevent data loss in case of malfunctioning To prevent data loss in case of malfunctioning

or lost devices.or lost devices. BackupBackup!! Backup has to be done periodically and often Backup has to be done periodically and often

manually manually up to date? up to date?

Many of these devices have, or soon, Many of these devices have, or soon, will have wireless connectivity.will have wireless connectivity.

Portable backup system

Mobile Computing Environments Mobile Computing Environments

IntroductionIntroduction Mobile devices (mobile telephones, Mobile devices (mobile telephones,

personal audio players, PDA, laptop personal audio players, PDA, laptop computers .. etc) are used in many computers .. etc) are used in many locations and environments than desktop locations and environments than desktop computers.computers.

Those devices continuously record user’s Those devices continuously record user’s

life artifacts.life artifacts.

Storage is mainly local to the device. Storage is mainly local to the device.

Mobile lost !Mobile lost !

BACKUP …

Introduction ..Introduction ..

SIM Card information backup machine

Mobile backup card USB 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:

Introduction ..Introduction ..- Mobile backup system:

Introduction ..Introduction .. The data volume and associated network The data volume and associated network

cost makes traditional backup to a backup cost makes traditional backup to a backup server cost prohibitive for most consumers.server cost prohibitive for most consumers.

What is needed is an What is needed is an automaticautomatic and ideally and ideally operating cost freeoperating cost free solution for mobile solution for mobile devices.devices.

Use short-range and peer-to-peer Use short-range and peer-to-peer communication capability. communication capability.

UbiStore: a backup architecture, where UbiStore: a backup architecture, where mobile devices backup their data over short-mobile devices backup their data over short-range, ad-hoc wireless links to other devices range, ad-hoc wireless links to other devices encountered as a result of user mobility.encountered as a result of user mobility.

UbiStoreUbiStoreMobile 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.

Table of contents: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.

Goals and constrains ..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 Only short-range, peer-to-peer

communication.communication. Maintain user’s privacy and data Maintain user’s privacy and data

integrity.integrity. Maximize the incentive to Maximize the incentive to

participate.participate.

Table of contents: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.

The exponential increase of mobile device’s The exponential increase of mobile device’s storage satisfy the user needs.storage satisfy the user needs.

The existence of free P2P communication The existence of free P2P communication (Blutooth) -> discovery mode.(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 : AssumptionsUbiStore overviews : Assumptions ....

UbiStore overviews : Evaluation UbiStore overviews : Evaluation

criteria ..criteria .. The recovery time:The recovery time: Time necessary to restore lost data. Time necessary to restore lost data. It is the most important parameter as it deals with direct It is the most important parameter as it deals with direct

user’s perception of the system’s performance. user’s perception of the system’s performance. The space efficiency:The space efficiency: Ratio between backup data and Ratio between backup data and

effective data. It is impacting the per-bit cost of the effective data. It is impacting the per-bit cost of the overall backup system. overall backup system.

The communication efficiency:The communication efficiency: reflects the reflects the communication overhead of using several peer-to-peer communication overhead of using several peer-to-peer communication links compared with centralized backup communication links compared with centralized backup mechanism.mechanism.

The paper present an initial evaluation of UbiStore using The paper present an initial evaluation of UbiStore using the the recovery timerecovery time criteria, for two different mobility criteria, for two different mobility models.models.

UbiStore overviews : Model ..UbiStore overviews : Model ..

A A node node in UbiStore is a software agent executed on in UbiStore is a software agent executed on a user’s device, and assigned a data area to be a user’s device, and assigned a data area to be backed up.backed up.

Encounter: the event of two nodes establishing Encounter: the event of two nodes establishing communication in the view to exchange data. communication in the view to exchange data.

At any time, each node in UbiStore operates in one At any time, each node in UbiStore operates in one of the following two modes:of the following two modes:

- Backup mode- Backup mode:: a node keeps sending data blocks a node keeps sending data blocks to other nodes while at the same time receiving to other nodes while at the same time receiving and storing data from other nodes.and storing data from other nodes.

- Recovery mode- Recovery mode:: used after a device failure or a used after a device failure or a lost device, where a node will seek to recover its lost device, where a node will seek to recover its data from any node encountered. data from any node encountered.

Table of contents: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.

ArchitectureArchitecture

Block: the elementary unit of storage in Block: the elementary unit of storage in UbiStore. UbiStore.

Blocks are immutable: once generated, they Blocks are immutable: once generated, they cannot be modified. cannot be modified.

Any block is assigned a globally unique Any block is assigned a globally unique identifier, associated with an owner. identifier, associated with an owner.

Blocks are not forwarded from one node to Blocks are not forwarded from one node to another node, i.e. a node will only send its another node, i.e. a node will only send its own blocks to another node.own blocks to another node.

- Block generation process:

Node Architecture ..Node Architecture ..

Node Architecture ..Node Architecture ..- UbiStore node functional overview:

Node Architecture: Data managerNode Architecture: Data manager

Choosing which block to send:Choosing which block to send:

Selecting blocks for deletion: blocks Selecting blocks for deletion: blocks to be deleted are chosen from the to be deleted are chosen from the tail of the queue (the blocks we are tail of the queue (the blocks we are most likely to encounter again in the most likely to encounter again in the short term are dropped first). short term are dropped first).

- Computing storage space offers: several strategies:

Node Architecture ..Node Architecture ..

Fixed size:Fixed size: a constant amount of storage a constant amount of storage space is advertised for each encounter. space is advertised for each encounter.

Adaptive:Adaptive: the offered storage space is the offered storage space is biased to favor frequently encountered biased to favor frequently encountered nodes, with longer contact durations -> nodes, with longer contact durations -> frequently encountered nodes are also likely frequently encountered nodes are also likely to be frequently encountered when it is time to be frequently encountered when it is time to recover the data after a failure.to recover the data after a failure.

Table of contents: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.

Evaluation: simulation mobility Evaluation: simulation mobility modelsmodels

The The random waypointrandom waypoint model in which nodes model in which nodes evolve in a two-dimensional square field with their evolve in a two-dimensional square field with their destination and speed determined randomly. destination and speed determined randomly.

This model is unrealistic and does not represent This model is unrealistic and does not represent any actual human mobility pattern, we use it to any actual human mobility pattern, we use it to (This will provide baseline).(This will provide baseline).

Commuters traveling on aCommuters traveling on a traintrain : high level of : high level of correlation between node movements. correlation between node movements.

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

The variation: recovery ratio vs. time (ratio=5) The variation: recovery ratio vs. time (ratio=5)

Evaluation: Simulation Evaluation: Simulation result ..result ..

Evaluation: Simulation result ..Evaluation: Simulation result ..

- 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.

Table of contents: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.

Related workRelated work

OceanStore and PAST: provide a self-organizing OceanStore and PAST: provide a self-organizing file system storage infrastructure to file system storage infrastructure to applications. applications.

PeerStore: is a backup system. Is not adapted PeerStore: is a backup system. Is not adapted to disconnected networks and opportunistic to disconnected networks and opportunistic communication.communication.

Pastiche: buddy have similar set of files. Pastiche: buddy have similar set of files. Buddies only exchange data that is not Buddies only exchange data that is not common for both.common for both.

Table of contents: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.

ConclusionConclusion The paper has presented the concept The paper has presented the concept

and initial design of UbiStore.and initial design of UbiStore. The main idea is to perform backup in The main idea is to perform backup in

other devices encountered by a mobile other devices encountered by a mobile device over time.device over time.

The paper presented an early The paper presented an early performance evaluation which shows performance evaluation which shows the benefit of exploiting repetitive the benefit of exploiting repetitive patterns in human mobility.patterns in human mobility.

Thank you ..