PPT-Consensus: Paxos Haobin Ni

Oct 22 2018 What is consensus A group of people go to the same place for the same meal A set of nodes have the same value for the same variable X 7 X7 X7 Why is it important In state machine replication SMR. Cheap Paxos a variant of the Paxos al gorithm guarantees liveness under the additional as sumption that the set of nonfaulty processors does not jump around too fast but uses only F 1 main pro cessors that actually execute the system and F auxiliar A Consensus Algorithm for . Fault Tolerant Replication. CS 5204 – Fall, 2008. System Model. Messages. possible indefinite delay. possible duplication or loss. delivered messages not corrupted. . . .. Advanced Topics in Computer Systems. Lecture 24. Paxos/Megastore. November . 26. th. , . 2012. John . Kubiatowicz. and Anthony D. Joseph. Electrical Engineering and Computer Sciences. University of California, Berkeley. Ken Birman. Fall 2012. Consensus… a classic problem. Consensus abstraction underlies many distributed systems and protocols. N processes. They start execution with inputs.  {0,1}. Asynchronous, reliable network. Replication. Lecture 16. , Oct 22. nd. 2015 . How’d we get here?. Failures & single systems; fault tolerance techniques added redundancy (ECC memory, RAID, etc.). Conceptually, ECC & RAID both put a “master” in front of the redundancy to mask it from clients -- ECC handled by memory controller, RAID looks like a very reliable hard drive behind a (special) controller. Recommendations for Consensus Statement Development Pilot Project (Resolution 14.4). Issues Brought Forward. Consensus in the development process is unanimous minus two but consensus from Congress is unanimous. Therefore, if someone does not agree with the consensus statement during the development process, it can still be passed along to Congress where it will likely be voted down.. Cezara. . Drăgoi. , INRIA ENS CNRS. Thomas A. . Henzinger. , IST Austria. Damien Zufferey. , MIT CSAIL. SNAPL, 2015.05.04. Fault-tolerant distributed algorithms. How to get it right when things go wrong ?. When you can’t agree to disagree. Consensus. Why do applications need consensus?. What does it mean to have consensus?. Consensus = consistency. Assumptions. Processes can choose values. Run at arbitrary speeds. View Change Protocols and Consensus COS 418: Distributed Systems Lecture 11 Mike Freedman Today View changes in primary-backup replication Consensus 2 Review: Primary-Backup Replication Nominate one replica Paxos and Replicated State Machine (RSM) Outline Basic Concepts of Replicated State Machine Paxos Made Simple Replicated State Machine We can replicate data, how can we guarantee it is correctly replicated? Lecture 16. , Oct 22. nd. 2015 . How’d we get here?. Failures & single systems; fault tolerance techniques added redundancy (ECC memory, RAID, etc.). Conceptually, ECC & RAID both put a “master” in front of the redundancy to mask it from clients -- ECC handled by memory controller, RAID looks like a very reliable hard drive behind a (special) controller. Each 42the OI 2DSeuTli and zPage wIIPwC hwaccuracy Page wcash Seive trading Page won iiaiiOtiS urior Oii7i bligaiioris 1Page wPaxos Page wIn MIX32 bSPage wiv ZZ Page wParticipant vJii reyuird O c27gQ Paxos. COS 418: Distributed Systems. Lecture . 10. Wyatt Lloyd. Let different replicas assume role of primary over time. System moves through a sequence of views. How do the nodes agree on view / primary?. L. anguage . for . Fault-tolerant Distributed . A. lgorithms. Cezara. . Drăgoi. , INRIA ENS CNRS. Thomas A. . Henzinger. , IST Austria. Damien Zufferey. , MIT CSAIL. POPL, 2016.1.21. 1. Motivation.