• Robert Hodges from Continuent presents
  • About Continuent
  • leading provider of open source database availability and scaling solutions
  • solutions
    • uni/cluster – multi-master database clustering that replicates data across multiple databases and load balances reads
    • uses "database virtualization"
  • scale-out design motivation
    • protection from db and site failures
    • continuous operation during upgrades
  • how come not everyone has it already?
  • creating identical replicas across different hosts is hard
    • Brewer's conjecture
  • trade-offs
    • DDL support
    • inconsistent reads between replicas
    • deadlocks
    • sequences
    • non-deterministic SQL
  • therefore many scale-out approaches are non-transparent
  • 3 basic scale-out technologies
    • data replication
    • where are updates processed? master/master vs master/slave
    • when are updates replicated? sync vs async
  • group communication – coordinates messages between distributed processes
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