Cheetah: An Economical Distributed RAM Drive

Current hard drive technology shows a widening gap between the ability to store vast amounts of data and the ability to process. To overcome the problems of this secular trend, we explore the use of available distributed RAM resources to effectively replace a mechanical hard drive. The essential approach is a distributed Linux block device that spreads its blocks throughout spare RAM on a cluster and transfers blocks using network capacity. The presented solution is LAN-scalable, easy to deploy, and faster than a commodity hard drive. The specific driving problem is I/O intensive applications, particularly digital forensics. The prototype implementation is a Linux 2.4 kernel module, and connects to Unix based clients. It features an adaptive prefetching scheme that seizes future data blocks for each read request. We present experimental results based on generic benchmarks as well as digital forensic applications that demonstrate significant performance gains over commodity hard drives