Fast VM Startup by Cooperative Image Caching for Cloud Data Centers

Virtual machine (VM) management is one of the key problems in cloud data centers. Many efforts have been put on finding an (approximate) optimal placement of VMs at physical machines (PMs) to achieve high resource utility. In this paper, we consider to reduce the startup delay of VMs, which is a key issue for improving user experience and resource utility. The basic idea of our work is to cache VM images at PMs so as to reduce the time of VM image retrieval. By handling VM placement and image placement jointly and de-centrally, we design a joint placement algorithm and an associated layered transport VM selection algorithm, so as to start VMs quickly in the meanwhile save some calculation resources. The key point of our algorithms lies in how to accelerate the startup of VM with limited information in a distributed fat-tree network. The proposed algorithms are evaluated by extensive simulations using a distributed system simulator SimGrid. The results show that our algorithms just lost a little performance in most cases, compared with the centralized algorithm and a classical cache placement strategy.