Comparison of disk I/O power consumption in modern virtualization

In Cloud Computing, the topic about hypervisors is the key research as it concerns management of physical resources and deployment virtual machines. Currently, modern hypervisors obtain new features to increase their performance under different architectures. Cloud data centers start to adopt techniques for power consumption management that can reduce the power, and meanwhile maintain the performance. In this paper, we investigate on the power consumption and performance issues concerning memory and disk I/O, comparing two open-source virtualization platforms: Xen and Kernel-based Virtual Machine (KVM). We compare Xen with raw disk and KVM´s different disk I/O types, including the write through, write back and none modes with the block sizes of 8, 64 and 128 KB, relating to web downloading and database query workload. The results show that the KVM write back mode can reduce about a half (56%) of power consumption comparing to Xen with raw disk when writing files and the KVM write through mode with page cache can reduce power consumption to about 3% of that consumed by Xen with raw disk when reading files. In case of performance, the speed of KVM when page cache can increase to about 26 times faster than the speed of Xen with raw disk. In case of memory, the VM´s power consumption is rather steady even when the memory usage varies.