Simulation of SSD’s Power Consumption

Abstract

In order to avoid changing existing infrastructures, SSDs need to fit in the same physical space of HDDs and, therefore, in their power envelope. Unfortunately, NAND power consumption is strongly dependent upon the Flash operation (i.e. read, write, erase). For many generations, SSD’s power has been over- or under-estimated by adopting the worst case power consumption scenario (i.e. assuming write operations all the time); this approach is running out of steam because it always leads to exceeding power specs with the most recent NAND technologies. In order to correctly evaluate power, it is necessary to estimate the number of operations per time interval and their specific type (read, write, erase). Simulations are the only practical way to address this problem: when the prototype is ready (especially if the controller is a multi-million dollar ASIC) there are no chances to significantly reduce power, it’s simply too late! This chapter shows how a SSD fine-grained simulator like SSDExplorer can be used as a design tool for developing power management algorithms that can minimize the power consumption of the entire SSD and, therefore, open the door to an even bigger adoption of SSDs (e.g. in data centers).