Saturday, April 26, 2014

Distributed Datа: Consistency

Don't Settle for Eventual Consistency - ACM Queue:

"Geo-replication brings two key benefits to Web services: fault tolerance and low latency. It provides fault tolerance through redundancy: if one data center fails, others can continue to provide the service. It provides low latency through proximity: clients can be directed to and served by a nearby data center to avoid speed-of-light delays associated with cross-country or round-the-globe communication. 

Geo-replication brings its challenges, however. The famous CAP theorem, conjectured by Brewer1 and proved by Gilbert and Lynch,7 shows it is impossible to create a system that has strong consistency, is always available for reads and writes, and is able to continue operating during network partitions."

Dont Settle for Eventual Consistency

This experiment shows that for this real-world workload Eiger's causal consistency and stronger semantics do not impose significant overhead.

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