Warcip

Abstract

The storage volume of SSDs has been greatly increased recently with emerging multi-layer 3D triple-level cell and quad-level cell. However, one critical overhead of any flash memory SSD is the garbage collection (GC) process that is necessary due to the inherent physical property of flash memories. GC is a time consuming process that slows down I/O performance and decreases endurance of SSD. To minimize the negative impact of GC, we introduce Write Amplification Reduction by Clustering I/O Pages (WARCIP). The idea is to use a clustering algorithm to minimize the rewrite interval variance of pages in a flash block. As a result, pages in a flash block tend to have a similar lifetime, minimizing write amplification during a garbage collection. We have implemented WARCIP on an enterprise NVMe SSD. Both simulation and measurement experiments have been carried out. Real world I/O traces and standard I/O benchmarks are used in our experiments to assess the potential benefit of WARCIP. Experiment results show that WARCIP reduces write amplification dramatically and the number of block erasures by 4.45 times on average, implying extended lifetimes of flash SSDs.