1. OceanStore/Tapestry Toward Global-Scale, Self-Repairing, Secure and Persistent Storage Anthony D. Joseph John Kubiatowicz Sahara Retreat, January 2003

2. OceanStore:2Sahara Retreat, January 2003 ©2003 UC Berkeley OceanStore Context: Ubiquitous Computing Computing everywhere: –Desktop, Laptop, Palmtop –Cars, Cellphones –Shoes? Clothing? Walls? Connectivity everywhere: –Rapid growth of bandwidth in the interior of the net –Broadband to the home and office –Wireless technologies such as CMDA, Satelite, laser Where is persistent data????

3. OceanStore:3Sahara Retreat, January 2003 ©2003 UC Berkeley Utility-based Infrastructure Pac Bell Sprint IBM AT&T Canadian OceanStore IBM Data service provided by storage federation Cross-administrative domain Pay for Service

4. OceanStore:4Sahara Retreat, January 2003 ©2003 UC Berkeley OceanStore Data Model Versioned Objects –Every update generates a new version –Can always go back in time (Time Travel) Each Version is Read-Only –Can have permanent name –Much easier to repair An Object is a signed mapping between permanent name and latest version –Write access control/integrity involves managing these mappings Comet Analogy updates versions

5. OceanStore:5Sahara Retreat, January 2003 ©2003 UC Berkeley The Path of an OceanStore Update Second-Tier Caches Multicast trees Inner-Ring Servers Clients

6. OceanStore:6Sahara Retreat, January 2003 ©2003 UC Berkeley Archival Dissemination of Fragments

7. OceanStore:7Sahara Retreat, January 2003 ©2003 UC Berkeley Tapestry

8. OceanStore:8Sahara Retreat, January 2003 ©2003 UC Berkeley Enabling Technology: DOLR (Decentralized Object Location and Routing) GUID1 DOLR GUID1 GUID2

9. OceanStore:9Sahara Retreat, January 2003 ©2003 UC Berkeley 4 2 3 3 3 2 2 1 2 4 1 2 3 3 1 3 4 1 1 43 2 4 NodeID 0xEF34 NodeID 0xEF31 NodeID 0xEFBA NodeID 0x0921 NodeID 0xE932 NodeID 0xEF37 NodeID 0xE324 NodeID 0xEF97 NodeID 0xEF32 NodeID 0xFF37 NodeID 0xE555 NodeID 0xE530 NodeID 0xEF44 NodeID 0x0999 NodeID 0x099F NodeID 0xE399 NodeID 0xEF40 NodeID 0xEF34 Basic Tapestry Mesh Incremental Prefix-based Routing

10. OceanStore:10Sahara Retreat, January 2003 ©2003 UC Berkeley Use of Tapestry Mesh Randomization and Locality

11. OceanStore:11Sahara Retreat, January 2003 ©2003 UC Berkeley Stability under Faults Instability is the common case….! –Small half-life for P2P apps (1 hour????) –Congestion, flash crowds, misconfiguration, faults Must Use DOLR under instability! –The right thing must just happen Tapestry is natural framework to exploit redundant elements and connections –Multiple Roots, Links, etc. –Easy to reconstruct routing and location information –Stable, repairable layer Thermodynamic analogies: –Heat Capacity of DOLR network –Entropy of Links (decay of underlying order)

12. OceanStore:12Sahara Retreat, January 2003 ©2003 UC Berkeley Single Node Tapestry Transport Protocols Network Link Management Application Interface / Upcall API OceanStore Application-Level Multicast Other Applications Router Routing Table & Object Pointer DB Dynamic Node Management

13. OceanStore:13Sahara Retreat, January 2003 ©2003 UC Berkeley It’s Alive! Planet Lab global network –98 machines at 42 institutions, in North America, Europe, Australia (~ 60 machines utilized) –1.26Ghz PIII (1GB RAM), 1.8Ghz PIV (2GB RAM) –North American machines (2/3) on Internet2 Tapestry Java deployment –6-7 nodes on each physical machine –IBM Java JDK 1.30 –Node virtualization inside JVM and SEDA –Scheduling between virtual nodes increases latency

14. OceanStore:14Sahara Retreat, January 2003 ©2003 UC Berkeley Segments of OceanStore within Sahara Retreat Today (5:30pm – 6:00pm) –OceanStore Long-Term Archival Storage Tomorrow morning session (8:30am-10:00am) –Tapestry status and deployment information

15. OceanStore:15Sahara Retreat, January 2003 ©2003 UC Berkeley For more info: http://oceanstore.org OceanStore vision paper for ASPLOS 2000 “OceanStore: An Architecture for Global-Scale Persistent Storage” OceanStore Prototype (FAST 2003): “Pond: the OceanStore Prototype” Tapestry algorithms paper (SPAA 2002): “Distributed Object Location in a Dynamic Network” Upcoming Tapestry Deployment Paper (JSAC) “Tapestry: a Global-Scale Overlay for Rapid Service Deployment” Probabilistic Routing (INFOCOM 2002): “Probabilistic Location and Routing” Upcoming CACM paper (not until February): –“Extracting Guarantees from Chaos”