Migrating enterprise storage to SSDs: analysis of tradeoffs

Recently, flash-based solid-state drives (SSDs) have becom e standard options for laptop and desktop storage, but their impact on enterprises has not been studied. Provisioning enterprise storage is challenging. It requires optimizing for the performance, capacity, power and reliability needs of the expected workload, all while minimizing financial costs. This paper, through analysis of a number of enterprise workloads, provides insights as to when, and how, SSDs should be incorporated into the enterprise storage hierarc hy. We describe an automated tool that, given device models and a block-level trace of a workload, determines the least-cost storage configuration. It analyzes the factors that drive th e configuration choice, and computes the price points at which different SSD-based solutions will become cost-effective. Our optimization framework is flexible and can be used to design a range of storage hierarchies. When applied to current workloads and prices we find the following in a nutshell: for many enterprise workloads capacity dominates provisioning costs and the current per-gigabyte price of SSDs is between a factor of 3 and 3000 times higher than needed to be cost-effective for full replacement. We find that SSDs can provide some benefit as an intermediate tier for caching and write-ahead logging in a hybrid disk-SSD configuration. Surprisingly, the power savings achieved by SSDs are comparable to power savings from using low-power SATA disks.