Abstract:
The availability of high-speed flash solid-state devices (SSD) has introduced a new tier into the memory hierarchy. SSDs have dramatically different properties than disks, yet are exposed in many systems as a generic block device. In this talk, I will present two systems that update the interface to these devices to better match their capabilities as a new memory tier.

First, I will talk about a system called FlashTier to use flash SSDs as a cache in front of slower disks. In this work, we investigate the numerous differences between the interface offered by an SSD, a persistent block store, and the service it provides, caching data. I will present how we redress these differences through new block-addressing and space-management techniques.

Next, I will describe our work on extending main memory by virtualizing it with inexpensive flash storage. We find that there are several paging mechanisms in the core virtual memory subsystem of the Linux kernel, which have been optimized for the characteristics of disks. I will describe a new flash-virtual memory system called FlashVM that de-diskifies these mechanisms for improved performance and reliability with flash SSDs.

Ph.D Defense Committee Members:
Michael M. Swift (chair), UW-Madison
Andrea C. Arpaci-Dusseau, UW-Madison
Remzi H. Arpaci-Dusseau, UW-Madison
Mark D. Hill, UW-Madison
Arif Merchant, Google