The Bleak Future of NAND Flash Memory

Laura M. Grupp, John Davis, Steven Swanson

10th USENIX Conference on File and Storage Technologies |

Published by USENIX

This is the final revision of the paper. There are two more earlier revisions available. The first revision used teh incorrect value for the baseline SSD. The second revision and third revision are indentical, except for where the revision statemtn is.

In recent years, flash-based SSDs have grown enormously both in capacity and popularity. In high performance enterprise storage applications, accelerating adoption of SSDs is predicated on the ability of manufacturers to deliver performance that far exceeds disks while closing the gap in cost per gigabyte. However, while flash density continues to improve, other metrics such as a reliability, endurance, and performance are all declining. As a result, building larger-capacity flashbased SSDs that are reliable enough to be useful in enterprise settings and high-performance enough to justify their cost will become challenging. In this work, we present our empirical data collected from 45 flash chips from 6 manufacturers and examine the performance trends for these raw flash devices as flash scales down in feature size. We use this analysis to predict the performance and cost characteristics of future SSDs. We show that future gains in density will come at significant drops in performance and reliability. As a result, SSD manufacturers and users will face a tough choice in trading off between cost, performance, capacity and reliability.