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arXiv · 1503.02654

Algorithms for Replica Placement in High-Availability Storage

K. Alex Mills·R. Chandrasekaran·Neeraj Mittal
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Abstract

A new model of causal failure is presented and used to solve a novel replica placement problem in data centers. The model describes dependencies among system components as a directed graph. A replica placement is defined as a subset of vertices in such a graph. A criterion for optimizing replica placements is formalized and explained. In this work, the optimization goal is to avoid choosing placements in which a single failure event is likely to wipe out multiple replicas. Using this criterion, a fast algorithm is given for the scenario in which the dependency model is a tree. The main contribution of the paper is an $O(n + \rho \log \rho)$ dynamic programming algorithm for placing $\rho$ replicas on a tree with $n$ vertices. This algorithm exhibits the interesting property that only two subproblems need to be recursively considered at each stage. An $O(n^2 \rho)$ greedy algorithm is also briefly reported.

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K. Alex Mills, R. Chandrasekaran, Neeraj Mittal. 2015-03-09. Algorithms for Replica Placement in High-Availability Storage. https://doi.org/10.1007/978-3-319-26626-8_26

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