1 / 9

Bidding for Storage Space in a Peer-to-Peer Data Preservation System

Protect important data collections by trading storage space in a peer-to-peer system through auctions and negotiations.

blancheb
Download Presentation

Bidding for Storage Space in a Peer-to-Peer Data Preservation System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Bidding for storage space in a peer-to-peer data preservation system • Protect important data collections from failure by making multiple copies. • Sites “trade” space, each site contributes storage resources to others and uses storage at others. • bid trading: mechanism where sites conduct auctions to decide who to trade with. • Constraints: limited resources and preserve autonomy (no central decision maker). • Negotiation and agreement in auction system in economics and computer science, first price, sealed bid auction. Every site is both producer and consumer. Profit is max reliability. • Mechanism (bid trading), different policies, simulation and exam results.

  2. Bid Trading: • archive site: autonomous provider of storage service to replicate data collection. • Local site proposes a trade request S bytes of space to remote sites. • If remote site agrees, two site swap deeds , the right of one site to use space at another site. • price B will be determined in trading negotiating, in fixed-price trading, S = B.

  3. Freedom in bidding: 1 Fixed-priced Bid: S=B 2 Adaptive Bids: follow same policy but take into account local condition. Example: f(R, S), free space R, and request S. 3 Multiple Policies: partitioned into classes, example: f1, f2,… 4 Maverick Site: same as multiple policies but with singe “maverick” site that has its own policy. 5 Free Market: each site has its own policy. 6 Malevolent Sites: Some sites break basic trading rules to subvert the system. PS: 5 and 6 called permissive scenarios are very hard to study.

  4. Reliability: • Each site calculate the local MTFF (mean time to failure); the expected time before one site collection is lost. • Trading:

  5. Adaptive Bid scenario: • Auction calling policy: rules for automatically deciding when to call and for what collection (1 CallForAll, or 2 CallForRare). • Bid policy: rules for automatically calculating the bid for each auction. • Selective I-P policies : I interval of potential bids (min and max bids), and P() the policy function. • General form: B = S * ( I * P() + (1 – I/2) ) • if P()=0, then symmetric bid policy. • P() policy function: • 1). FreeSpace: P() = K/T • 2). UsedSpace: P() = (T-K)/T • 3). AbundantCollection: P() = C/G • 4). RareCollection: P() = (G-C)/G • PS: K: local free space, T: local space, C: # of copies of rarest collections, G: goal # of copies

  6. Rheeve: A Plug-n-Play Peer-to-Peer Communication Platform • Platform supports HTTP-enabled, efficient and fault tolerant P2P application. • P2P is distributed system where nodes play equal roles and have ability to discover and connect each other and share information and services. Example: Napster, SETI@HOME. • Peer discover: 1) Centralize algorithm; file indexing server to direct P2P file sharing. 2) Distributed algorithm: gossip to discover peers and services. 3) Hybrid version. • System Architecture: • Each peer is identified by an UCI (Universal Connection Identifier); consists a protocol name, address, and port #. • Four layers: • 1) Lowest layer: HTTP over internet, • 2) Second layer: programming platform and OS,

  7. 3) third layer: Rheeve’s peer platform which handles peer management, service management, and utilities. • 4) top layer: P2P application via visual interface or API. • Connection Management • When a node starts, it connects to well-known server which maintains an up-to-date list of locations UCI of on-line peers. • Download the list so it can connect to other peers. • The server maintains small # of peer UCIs. • Using HTTP query to download UCIs in FIFO order. • Starting peer broadcast in LAN to notify all other peers by UDP. • Since finding disjoint peer has smaller probability, Rheeve uses mobile agent-enabled approach to connect disjoint peer groups.

  8. The mobile agent-enabled auxiliary server (such as IBM’s Aglets) download UCIs from well-known server, dispatch a mobile agent traveling across nodes, capture UCIs and create another mobile agent and continue to travel. • Periodically record UCIs into a log file; it is used when a peer shutdown and restarted. • Periodically downlown UCI list from known peers as a backup for connection instability. • Service Discovery: • Periodically announce services to its known peers and receiving peers registers the service and provider. • Forward new service to other known peers. • Service Delivery: • Search local registration list first, if not found, ask service source from the forward.

  9. Resource Management: • To efficiently manage local resource on peer node, Rheeve has three modules. • 1) Listener Manager module: handle all incoming requests • 2) Updater: updating for piece of code that need to be executed periodically. • 3) File Manager: abstraction over file system so P2P is independent of file system and security. • Application Control: • Control the execution of P2P applications such as loading and stopping operations, also coordinates with file manager. • Communication Mechanism: • Use HTTP (crossing firewalls) and XML.

More Related