Data Management in Distributed
Systems
Minqi Zhou
Software Engineering Institute
Office: Room 111 Mathematics Building
E-mail: mqzhou@sei.ecnu.edu.cn
Phone: 32204750-167
2010-09-16
Course Introduction
• Data Management in P2P Systems
– 1-4 weeks
• Data Management in Cloud Systems
– 5-10 weeks
• Computational Advertisement
– 11-18 weeks
Final Grades
• Usual Grades (60%)
– Attendance
– Presentation
• Final Report (40%), (English Preferred)
– Survey
– Paper
A Brief Introduction to
Distributed Systems
What Is a Distributed System?
• Multiple computers (“machines,” “hosts,”
“boxes,” &c.)
– Each with CPU, memory, disk, network interface
– Interconnected by LAN or WAN (e.g., Internet)
• Application runs across this dispersed
collection of networked hardware
• But user sees single, unified system
5
What Is a Distributed System?
(Alternate Take)
“A distributed system is one in which the failure
of a computer you didn't even know existed can
render your own computer unusable.”
– Leslie Lamport, Microsoft Research (ex DEC)
6
Start Simple: Centralized System
• Suppose you run Gmail
• Workload:
– Inbound email arrives; store on disk
What are shortcomings of this design?
– Users retrieve, delete their email
• You run Gmail on one server with disk
Email
Reader
Email
Reader
Email
Reader
Email
Sender
Gmail
Server (PC)
Email
Sender
Email
Sender
7
Why Distribute?
For Availability
• Suppose Gmail server goes down, or network
between client and it goes down
• No incoming mail delivered, no users can read their
inboxes
• Fix: replicate the data on several servers
– Increased chance some server will be reachable
– Consistency? One server down when delete message, then
comes back up; message returns in inbox
– Latency? Replicas should be far apart, so they fail
independently
– Partition resilience? e.g., airline seat database splits, one
seat remains, bought twice, once in each half!
8
Why Distribute?
For Scalable Capacity
• What if Gmail a huge success?
• Workload exceeds capacity of one server
• Fix: spread users across several servers
– Best case: linear scaling—if U users per box, N
boxes support NU users
– Bottlenecks? If each user’s inbox on one server,
how to route inbound mail to right server?
– Scaling? How close to linear?
– Load balance? Some users get more mail than
others!
9
Performance Can Be Subtle
• Goal: predictable performance under high
load
• 2 employees run a Starbucks
– Employee 1: takes orders from customers, calls
them out to Employee 2
– Employee 2:
• writes down drink orders (5 seconds per order)
• makes drinks (10 seconds per order)
• What is throughput under increasing load?
10
Starbucks Throughput
• Peak system performance: 4 drinks / min
What would preferable curve be?
•
What
happens
when
load
>
4
orders
/
min?
What design achieves that goal?
• What happens to efficiency as load increases?
11
Why Are Distributed Systems
Hard to Design?
• Failure: of hosts, of network
– Remember Lamport’s lament
• Heterogeneity
– Hosts may have different data representations
• Need consistency (many specific definitions)
– Users expect familiar “centralized” behavior
• Need concurrency for performance
– Avoid waiting synchronously, leaving resources idle
– Overlap requests concurrently whenever possible
12
References
• Books
– Legitimate applications of peer-to-peer networks。 Dinesh Verma。
Wiley-IEEE, 2004
– Cloud Computing: Web-Based Applications That Change the Way You
Work and Collaborate Online。Michael Miller， Que, 2008。
– F. von Lohmann, “P2P File ShDavid P. Anderson and John Kubiatowicz,
The Worldwide Computer, Scientific American, March 2002
• Papers
– Ion Stoica, Robert Morris, David Karger, M. Frans Kaashoek, Hari
Balakrishnan, “Chord: A Scalable Peer-to-peer Lookup Service for
Internet Applications”, Proceedings of ACM SIGCOMM’01, San Diego,
CA, August 2001.
– Bujor Silaghi, Bobby Bhattacharjee, Pete Keleher, “Query Routing in
the TerraDir Distributed Directory”, Proceedings of SPIE ITCOM, Boston,
MA, July 2002.
– Sylvia Ratnasamy, Paul Francis, Mark Handley, Richard Karp, Scott
Shenker, “A Scalable Content-Addressable Network”, Proceedings of
ACM SIGCOMM’01, San Diego, CA, August 2001.
– OceanStore: An Architecture for Global-Scale Persistent Storage , John Kubiatowicz,
David Bindel, Yan Chen, Steven Czerwinski, Patrick Eaton, Dennis Geels,
Ramakrishna Gummadi, Sean Rhea, Hakim Weatherspoon, Westley Weimer, Chris
Wells, and Ben Zhao. Appears in Proceedings of the Ninth international
Conference on Architectural Support for Programming Languages and Operating
Systems (ASPLOS 2000), November 2000
– W. J. Bolosky, J. R. Douceur, D. Ely, M. Theimer; Feasibility of a Serverless
Distributed File System Deployed on an Existing Set of Desktop PCs, Proceedings of
the international conference on Measurement and modeling of computer systems,
2000, pp. 34-43
– J. Kleinberg, The Small-World Phenomenon: An Algorithmic Perspective, Proc. 32nd
ACM Symposium on Theory of Computing, Portland, OR, May, 2000
– R. Albert, H. Joeong, A. Barabasi, Error and Attack Tolerance of Complex Networks,
Nature, vol. 46, July 2000.
– H. Zhang, A. Goel, R. Govindan, Using the Small-World Model to Improve Freenet
Performance, Proceedings of IEEE Infocom, New York, NY, June 2002.
– J. Chu, K. Labonte, B. Levine, Availability and Locality Measurements of Peer-toPeer File Systems, Proceedings of SPIE ITCOM, Boston, MA, July 2002.
– R. Bhagwan, S. Savage, G. Voelker, Understanding Availability, in Proc. 2nd
International Workshop on Peer-to-Peer Systems (IPTPS), Berkeley, CA, Feb 2003.
– S. Saroiu, P. Gummadi, S. Gribble, A Measurement Study of Peer-to-Peer File
Sharing Systems, in Proceedings of Multimedia Computing and Networking 2002
(MMCN'02), San Jose, CA, January 2002.
– aring and Copyright Law: A Primer for Developers,” IPTPS 2003
– Antony Rowstron and Peter Druschel, “Pastry: Scalable, Decentralized,
Object Location and Routing for Large-scale Peer-to-peer Systems”,
Proceedings of IFIP/ACM International Conference on Distributed
Systems Platforms (Middelware)’02
– Ben Y. Zhao, John Kubiatowicz, Anthony Joseph, “Tapestry: An
Infrastructure for Fault-tolerant Wide-area Location and Routing”,
Technical Report, UC Berkeley
– A. Rowstron and P. Druschel, "Storage management and caching in
PAST, a large-scale, persistent peer-to-peer storage utility", 18th ACM
SOSP'01, Lake Louise, Alberta, Canada, October 2001.
– S. Iyer, A. Rowstron and P. Druschel, "SQUIRREL: A decentralized, peerto-peer web cache", appeared in Principles of Distributed Computing
(PODC 2002), Monterey, CA
– Frank Dabek, M. Frans Kaashoek, David Karger, Robert Morris, and Ion
Stoica, Wide-area cooperative storage with CFS, ACM SOSP 2001, Banff,
October 2001
– Ion Stoica, Daniel Adkins, Shelley Zhaung, Scott Shenker, and Sonesh
Surana, Internet Indirection Infrastructure, in Proceedings of ACM
SIGCOMM'02, Pittsburgh, PA, August 2002, pp. 73-86
– L. Garces-Erce, E. Biersack, P. Felber, K.W. Ross, G. Urvoy-Keller,
Hierarchical Peer-to-Peer Systems, 2003,
http://cis.poly.edu/~ross/publications.html
– Kangasharju, K.W. Ross, D. Turner, Adaptive Content Management in
Structured P2P Communities, 2002,
http://cis.poly.edu/~ross/publications.html
– K.W. Ross, E. Biersack, P. Felber, L. Garces-Erce, G. Urvoy-Keller, TOPLUS:
Topology Centric Lookup Service, 2002,
http://cis.poly.edu/~ross/publications.html
– P. Felber, E. Biersack, L. Garces-Erce, K.W. Ross, G. Urvoy-Keller, Data
Indexing and Querying in P2P DHT Networks,
http://cis.poly.edu/~ross/publications.html
– K.W. Ross, Hash-Routing for Collections of Shared Web Caches, IEEE
Network Magazine, Nov-Dec 1997
– A. Keromytis, V. Misra, D. Rubenstein, SOS: Secure Overlay Services, in
Proceedings of ACM SIGCOMM'02, Pittsburgh, PA, August 2002
– M. Reed, P. P. Syverson, D. Goldschlag, Anonymous Connections and
Onion Routing, IEEE Journal on Selected Areas of Communications,
Volume 16, No. 4, 1998.
– V. Scarlata, B. Levine, C. Shields, Responder Anonymity and
Anonymous Peer-to-Peer File Sharing, in Proc. IEEE Intl. Conference on
Network Protocols (ICNP), Riverside, CA, November 2001.
– E. Sit, R. Morris, Security Considerations for Peer-to-Peer Distributed
Hash Tables, in Proc. 1st International Workshop on Peer-to-Peer
Systems (IPTPS), Cambridge, MA, March 2002.
– J. Saia, A. Fiat, S. Gribble, A. Karlin, S. Sariou, Dynamically FaultTolerant Content Addressable Networks, in Proc. 1st International
Workshop on Peer-to-Peer Systems (IPTPS), Cambridge, MA, March
2002.
– M. Castro, P. Druschel, A. Ganesh, A. Rowstron, D. Wallach, Secure
Routing for Structured Peer-to-Peer Overlay Netwirks, In Proceedings
of the Fifth Symposium on Operating Systems Design and
Implementation (OSDI'02), Boston, MA, December 2002.
– Edith Cohen and Scott Shenker, “Replication Strategies in Unstructured
Peer-to-Peer Networks”, in Proceedings of ACM SIGCOMM'02,
Pittsburgh, PA, August 2002
– Dan Rubenstein and Sambit Sahu, “An Analysis of a Simple P2P
Protocol for Flash Crowd Document Retrieval”, Columbia University
Technical Report