I. Introduction
NVMe SSD-based all-flash array (AFA) systems recently receive serious attention from industry because their low latency and high throughput can aid various applications such as high-performance computing and real-time big data analysis [1]. An AFA also offers plenty of other benefits over disk storage - it consumes less power, does not require as much cooling as HDDs, and takes up less floor space. Thanks to all those benefits, an AFA is emerging as fast and economic storage solutions, rapidly replacing existing HDD-based storage clusters in data centers.