Design and Implementation of an Out-of-Band Virtualization System for Large SANs

Out-of-band virtualization intrinsically has the potential to provide high performance and good scalability. Unfortunately, existing out-of-band virtualization systems have some limitations, such as restrictions to specific platforms and/or hardware. In this paper, we present a new out-of-band virtualization system, MagicStore, which is not limited to any specific hardware and supports three widely used host platforms: Windows, Solaris, and Linux. First, MagicStore uses the SLAS2 approach to scale round-robin striped volumes efficiently. Second, it survives panics and power failures robustly through a combination of lazy synchronizations, ordered writes, and REDO logging. Third, it also incorporates typical legacy storage quickly by analyzing partition tables and reconstructing logical volumes. Our evaluation results from representative experiments demonstrated that MagicStore has the ability to provide high performance, to introduce low processor overhead, and to have good scalability.