Optimal Storage Allocation for Wireless Cloud Caching Systems with a Limited Sum Storage Capacity

TL;DR

This paper analyzes the recovery failure probability in wireless cloud storage systems with limited total storage, deriving optimal storage allocation strategies for different SNR regimes to improve system reliability.

Contribution

It provides an asymptotic analysis of failure probability and identifies optimal storage allocations for high and low SNR regimes in wireless cloud storage.

Findings

Maximal symmetric allocation is optimal at high SNR.

Minimal allocation with complete and partial nodes is optimal at low SNR.

Intermediate SNR regimes favor choosing between the two extremes.

Abstract

In wireless cloud storage systems, the recovery failure probability depends on not only wireless channel conditions but also storage size of each distributed storage node. For an efficient utilization of limited storage capacity and the performance characterization of allocation strategies, we asymptotically analyze the recovery failure probability of a wireless cloud storage system with a sum storage capacity constraint for both high SNR regime and low SNR regime. Then, we find the optimal storage allocation strategy across distributed storage nodes in terms of the asymptotic recovery failure probability. Our analysis reveals that the maximal symmetric allocation is optimal for high SNR regime and the minimal allocation (with $\lfloor T\rfloor$ complete storage nodes and an incomplete storage node) is optimal for low SNR regime, where $T$ is the sum storage capacity. Based on the numerical investigation, we also show that in intermediate SNR regime, a balance allocation between the minimal allocation and the maximal symmetric allocation would not be required if we select one between them according to SNR.