EC-Store: Bridging the Gap between Storage and Latency in Distributed Erasure Coded Systems

Abstract

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Cloud storage systems typically choose between replicating or erasure encoding data to provide fault tolerance. Replication ensures that data can be accessed from a single site but incurs a much higher storage overhead, which is a costly downside for large-scale storage systems. Erasure coding has a lower storage requirement but relies on encoding/decoding and distributed data retrieval, which can result in straggling requests that increase response times. We propose strategies for data access and data movement within erasure-coded storage systems that significantly reduce data retrieval times. We present EC-Store, a system that incorporates these dynamic strategies for data access and movement based on workload access patterns. Through detailed evaluation using two benchmark workloads, we show that EC-Store incurs significantly less storage overhead than replication while achieving better performance than both replicated and erasure-coded storage systems.