21,342 research outputs found
CATS: linearizability and partition tolerance in scalable and self-organizing key-value stores
Distributed key-value stores provide scalable, fault-tolerant, and self-organizing
storage services, but fall short of guaranteeing linearizable consistency
in partially synchronous, lossy, partitionable, and dynamic networks, when data
is distributed and replicated automatically by the principle of consistent hashing.
This paper introduces consistent quorums as a solution for achieving atomic
consistency. We present the design and implementation of CATS, a distributed
key-value store which uses consistent quorums to guarantee linearizability and partition tolerance in such adverse and dynamic network conditions. CATS is
scalable, elastic, and self-organizing; key properties for modern cloud storage
middleware. Our system shows that consistency can be achieved with practical
performance and modest throughput overhead (5%) for read-intensive workloads
Delay Tolerant Networking over the Metropolitan Public Transportation
We discuss MDTN: a delay tolerant application platform built on top of the Public Transportation System (PTS) and able to provide service access while exploiting opportunistic connectivity. Our solution adopts a carrier-based approach where buses act as data collectors for user requests requiring Internet access. Simulations based on real maps and PTS routes with state-of-the-art routing protocols demonstrate that MDTN represents a viable solution for elastic nonreal-time service delivery. Nevertheless, performance indexes of the considered routing policies show that there is no golden rule for optimal performance and a tailored routing strategy is required for each specific case
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