Risk Aware Provisioning and Resource Aggregation Based Consolidation of Virtual Machines

Server consolidation has emerged as an important technique to save on energy costs in virtualized datacenters. The issue of instantiation of a given set of Virtual Machines (VMs) on a set of Physical Machines (PMs) can be thought of as consisting of a provisioning step where we determine the amount of resources to be allocated to a VM and a placement step which decides which VMs can be placed together on a physical machines thereby allocating VMs to PMs. In this paper, we introduce a provisioning scheme which takes into account acceptable intensity of violation of provisioned resources. In addition we identify a serious shortcoming of existing placement schemes that correct in our correlation aware placement scheme. We consider correlation among aggregated resource demands of VMs while finding the VM-PM mapping. Experimental results reveal that our approach leads to a significant amount of reduction in the number of servers (up to 32% in our settings) required to host 1000 VMs and thus enables us to turn off unnecessary servers. It achieves this by packing VMs more tightly by correlating resource requirements across the entire set of VMs to be placed. We present a comprehensive set of experimental results comparing our scheme with the existing provisioning and placement schemes.