Geo-aware erasure coding for high-performance erasure-coded storage clusters

Erasure code-based distributed storage systems are increasingly being used by storage providers for big data storage since they offer the same reliability as replication with a significant decrease in the amount of storage required. But, when it comes to a storage system with data nodes spread across a very large geographical area, the node's recovery performance is affected by various factors that are both network and computation related. In this paper, we present a XOR-based code supplemented with the ideas of parity duplication and rack awareness that could be adopted in such storage clusters to improve the recovery performance during node failures and compare it with popular implementations of erasure codes, namely Facebook's Reed-Solomon codes and XORBAS local recovery codes. The code performance along with the proposed ideas are evaluated on a geo-diverse cluster deployed on the NeCTAR research cloud. We also present a scheme for intelligently placing blocks of coded storage depending on the design of the code, inspired by local reconstruction codes. The sum of all these propositions could offer a better solution for applications that are deployed on coded storage systems that are geographically distributed, in which storage constraints make triple replication not affordable, at the same time ensuring minimal recovery time is a strict requirement.