A Mechanism of Flexible Memory Exchange in Cloud Computing Environments

In cloud computing environment, virtual machine technology is used as a means of flexibly assigning workloads to real machines based on the workloads' static profiles. Though this technology aims at flexible and dynamic resource sharing, memory is underutilized in cloud environments. We propose a virtual swap management mechanism (VSMM) that enables flexible and dynamic memory sharing via a local area network. The VSMM can virtualize swap devices seen by a guest operating system (OS), and transparently switch underlying physical devices to that OS. In this paper, we explain the VSMM architecture and provide details on our prototype implementation using the Xen open source hyper visor, open source iSCSI implementations, and logical volume management. Through various experiments, we demonstrate that VSMM can contribute to improving process performance and maximally utilizing the equipped memory in cloud environments.