A demand-driven virtual disk prefetch mechanism for seamless mobility of personal computing environments

Abstract

In this paper, we propose a demand-driven virtual disk (VD) prefetch mechanism—DPM—to improve the performance of virtual machine (VM) at destination site for mobile personal computing environments. DPM uses an extended CoW (Copy-on-Write) virtual block device to split the traditional monolithic large-sized VD image into multiple small-sized SVD (Software Virtual Disk) images at a basic granularity of a single kind of software. Based on the fine-grained VD splitting, DPM uses an access frequency and dynamic priority-based prefetch target identifying-APTI algorithm to identify the SVDs of the software being used by the user at destination site, and prefetches those SVDs by utilizing P2P transportation mechanism at background. We have built a prototype to realize DPM on Xen virtual machine monitor (VMM). Experiments on the prototype show that DPM can effectively improve the VM performance at an unexpected destination site without any cached VD state, being helpful in achieving seamless mobility of personal computing environments in distributed virtual machine environments.