  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.
