The effects of consolidation and containment
Consolidation makes multiple virtual servers share the physical resources of the one device on which they reside. Together with containment, which is to choose virtual machines instead of adding new physical devices, this results in less hardware and electricity being used per server. Running multiple servers on a physical device, makes virtualization decrease the amount of information technology waste and reduce energy use, as they all access the same pool of resources.
Virtualization brings new ways to save energy in data centers
Data centers consist of racks of servers, networks, storage hardware, power, power backup, and cooling facilities. To reduce electricity consumption, there are methods for more efficient cooling, like raised floors or empty slots for cool air to flow more freely, using hot and cold aisles. Data centers can even do lights-out to consume less energy. During off-peak periods, virtual machines can be migrated to other devices for the possibility of shutting down parts of the data center to reduce power consumption.
Power Consumption Savings
Before virtualization became publicly available, the idea of one application per server resulted in server sprawl. With new servers constantly being required, more data centers were built, which consumed even more energy for power and cooling. Virtualization mitigated this by consolidating several virtual servers onto only one physical device. According to the IDC analysis from 2016, the power consumption savings between 2003 and 2015 was 215,71%, with the use of virtualization products from VMWare alone, as seen in figure 1. This analysis did not take into account power for cooling. (Gillen, et al., 2016)
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