Solid State Disk Object-Based Storage with Trim Commands

This paper presents a model of NAND flash SSD utilization and write amplification when the ATA/ATAPI SSD Trim command is incorporated into object-based storage under a variety of user workloads, including a uniform random workload with objects of fixed size and a uniform random workload with objects of varying sizes. We first summarize the existing models for write amplification in SSDs for workloads with and without the Trim command, then propose an alteration of the models that utilizes a framework of object-based storage. The utilization of objects and pages in the SSD is derived, with the analytic results compared to simulation. Finally, the effect of objects on write amplification and its computation is discussed along with a potential application to optimization of SSD usage through object storage metadata servers that allocate object classes of distinct object size.