White Paper Green Desktop Infrastructure An Approach to Reduce Desktop Carbon Footprint The proliferation of desktops is increasingly contributing to carbon emissions, through inefficient power consumption, heat generation and subsequent cooling requirements. Desktops have long been ignored from strategic IT efficiency and optimization initiatives. Traditional Green initiatives are no longer effective in addressing massive carbon emissions. There is a need to adopt alternative and pathbreaking approaches to leverage diminishing natural resources, control rising costs, and go GREEN. This paper provides an insight into the need for Green Desktops and a transformational solution and reference architecture for implementing a future-ready cloud-enabled Green Desktop Computing framework.
About the Author Ankur Srivastava Ankur Srivastava is a Solution Architect working with the Hi-Tech Industry Solution Unit (ISU) of TCS and currently leads the TCS NetApp Solutions Lab. His main areas of focus are Storage, Database and Virtualization. He has close to eight years of experience as a technologist, delivering solutions across technology stacks covering storage, servers, databases and applications. Ankur holds a Bachelor of Technology (B. Tech) degree in Computer Science and Engineering and is also a NetApp Certified Implementation Engineer (NCIE). 2
Table of Contents 1. Introduction 4 2. Traditional Green Desktops 4 Introduction 4 Approach Analysis 4 Approach Evolution 5 3. Green Desktop Infrastructure 5 Introduction 5 Approach Analysis 5 Reference Architecture 6 Test Results & Business Benefits 8 4. Conclusion 13 5. References 13 3
Introduction With compelling growth opportunities and rapid expansion plans, organizations today are considering mergers and acquisitions to improve time-to-market. These have resulted in rapid changes in employee numbers, leading to proliferation of desktops to address business objectives. These desktops are mostly procured on demand forecast and have very limited prior architectural or deployment planning. This results in distributed desktop silos with increasing power and energy demands. Desktop computers have an average useful lifespan of three to four years after which technology evolution renders them unusable or inefficient. These then need to be replaced with new desktops to match the evolving technology needs and leverage new technology benefits. This technology refresh creates a huge amount of electronic waste (or e-waste) requiring special disposal. These disposal costs are recurring in nature and contribute to the overall cost of desktop ownership and operation. Desktops today also need to be available and running round the clock. Given the fact that a single desktop per user consumes significant power, when scaled-up to tens of thousands of desktops, power consumption can drastically affect the overall IT budget and future cost-control strategies. Increasing costs of desktop ownership and high energy demands are driving organizations to explore efficient IT strategies to reduce their carbon footprint and optimally leverage shrinking natural resources. In the article, Harnessing Green IT: Principles and Practices, San Murugesan defines the field of green computing as "the study and practice of designing, manufacturing, using and disposing of computers, servers and associated subsystems such as monitors, printers, storage devices and networking and communications systems efficiently and effectively with minimal or no impact on the environment. Green desktops are aimed at maximizing energy efficiency and reducing the generation of e-waste through effective utilization of desktop computing resources such as CPU, memory and hard drives. Traditional Green Desktops Introduction Traditional approach to green desktops was confined to the Corporate Social Responsibility (CSR) initiatives of companies. Traditional approaches involved user awareness sessions on the implications of high carbon footprint and ways to reduce desktop power consumption. Approach Analysis As a preliminary step to environment conservation, users were requested to switch off their monitors, and keep their computers in sleep/stand-by/hibernate mode when not in use. However, the success of these initiatives was dependent on the users discretion and their sensitivity to the environment. Even an environment sensitive user could, at times, forget to adopt these practices, rendering the approach ineffective and inefficient. 4
Hardware Original Equipment Manufacturers (OEMs) have also taken on a green initiative to create energy efficient desktops and improve the disposal of e-waste from their products. The Environment Protection Agency (EPA) conceived the Energy Star Program to certify products based on their electricity consumption. However, these initiatives alone are not sufficient to address the pressing issue of the carbon footprint being generated by the organizations. With operating systems evolving over time, power management settings to automatically switch off or bring the idle computer to stand-by/sleep mode came into being. Such automatic power management is often not recommended because desktop backup and maintenance activities are often scheduled during off-peak hours when desktops are not being used. This also reduces the overall end-user experience as desktops need to be rebooted at the start of each day and users have to wait for logon scripts to execute and the desktop to be ready for use. Another technique often adopted by organizations is to allocate one desktop to more than one user based on the availability. Through this, utilization of existing desktops can be increased, reducing the need to procure additional desktops. However, in this approach the actual number of desktops in use remains the same. Also, existing desktops can never utilize 100% of their available resources because at their peak workload, users may face performance degradation. For realizing real and tangible cost benefits, increase in desktop utilization should be coupled with the reduction in the actual energy required to keep the desktops running. Approach Evolution Virtualization is fast proving to be the preferred solution for going green, additionally benefiting organizations through reduced overall operational expenditure (OPEX) and capital expenditure (CAPEX). Virtualization reduces the total number of physical servers running in the datacenter by consolidating multiple virtual servers into one physical server. Thus far, virtualization as an optimization process has been confined to datacenter strategies with desktops excluded from this process. Green Desktop Infrastructure Introduction Virtualization is fast proving to be the preferred solution for going green, additionally benefiting organizations through reduced overall operational expenditure (OPEX) and capital expenditure (CAPEX). Virtualization reduces the total number of physical servers running in the datacenter by consolidating multiple virtual servers into one physical server. Thus far, virtualization as an optimization process has been confined to datacenter strategies with desktops excluded from this process. Approach Analysis Desktop virtualization is the process of hosting desktops in a virtualized datacenter and providing virtual desktops to information workers. Desktop virtualization gives system administrators the ability to host and manage virtual machines in a centrally located datacenter and the end-user, a full desktop computer experience. Virtualization helps consolidate desktops on the server hardware and, thus, reduce the overall 5
workspace and power requirements. It also helps in remote access of desktops and in addressing mobility requirements of the end-users. Desktop virtualization can be leveraged to integrate different virtualization technology components into an efficient Virtual Desktop Infrastructure (VDI). VDI is a variation of the traditional server-based computing (SBC) model where a single operating system image is shared across multiple users. From the end-user perspective, an SBC model provides a many-to-one relationship while a VDI works on a one-to-one relationship between end-clients and operating systems. Reference Architecture Green Desktop Infrastructure setup requires integration of multiple software technology components for end-to-end desktop delivery. Figure 1: Server-Based Computing Figure 2: Virtual Desktop Infrastructure 6
Shared storage is a key component of the technology stack - it provides a centralized storage repository for storing virtual machine images and user data. Centralized storage provides the much needed consolidation platform for the entire distributed desktop infrastructure. Storage reduction techniques Figure 3: Green Desktop Technology Stack such as data de-duplication and thin provisioning reduce the overall storage requirements significantly in VDI environments. This is possible because the VDI environment consists of multiple images of the same operating systems on a single shared storage and de-duplication technology is capable of removing duplicate blocks from the storage. So, there are lesser moving parts involved in data storage providing huge energy benefits as compared to a similar setup with traditional desktop infrastructure. The compute platform comprises server infrastructure capable of hosting the virtual environment and connects to the organizational network. It is used for setting up the hypervisor for hosting the virtual infrastructure. The hypervisor is responsible for segregating the physical pool of hardware resources and 7
sharing it across the virtual infrastructure. This entire operation is transparent to the virtual machine. Hypervisors provide huge consolidation ratios, thereby reducing the number of moving hardware parts significantly. This enables replacement of multiple physical desktops with a single hardware server thereby improving the overall operational efficiency. The application virtualization platform helps in rendering the virtualized applications to the end-user desktops based on user profiling requirements. Applications can be virtualized and made independent of the underlying hardware and software platform and can be streamed directly to the end-user desktops. This is an optional component in a typical VDI setup and can be used based on the requirement. The VDI Connection Broker is a key component, taking care of authentication and authorization of desktop users and mapping users to their corresponding desktops. It allows for the creation of desktop pools based on user workload or end-user profiles. Desktops in the pool are pre-configured based on user requirements and entitled to virtual desktops. The desktop connection broker is tightly integrated with the Active Directory allowing seamless user and desktop management. From the end-user perspective, the virtual machines are accessible from a variety of end-client devices such as thin clients, traditional or refurbished desktop PCs or mobile and handheld devices. The solution allows for a Bring-Your-Own-PC (BYOP) model where users can bring any end-user devices and get their personalized virtual desktops streamed and loaded to their devices. Desktops created from a VDI solution can either be persistent or non-persistent. Non-persistent desktops are destroyed at the end of the user session, thereby providing great physical resource sharing. This is possible because only the desktops that are being used by users are available and contributing to the physical resource consumption. This model improves the consolidation ratio of virtual desktops to physical servers even more significantly. Test Results and Business Benefits A proof-of-concept (PoC) on VDI was conducted at the TCS NetApp Solutions Lab to assess the amount of savings that can be achieved by replacing physical desktops with virtual desktops. We conducted the PoC on VMware VDI technology components using NetApp storage controllers. We also conducted scalability tests to determine the number of Virtual Machines (VMs) (with medium load and Win 7 as Guest OS) that can be used on an ESX host without noticeable system performance degradation. These tests were performed on a Dell 2950 series server with two quad core CPUs (8 * 2.66 GHz) and an 8 GB RAM hosting VMware ESX server with 75 virtual machines on a 1 Gigabit network. The datastores for the virtual machines were created on the iscsi LUNs provisioned through NetApp FAS3140 Storage System. We started the virtual machines on the ESX host in batches of five VMs at a time and captured the corresponding ESX host performance metrics (CPU and Memory) in the graphs shown in Figures 4 and 5 The performance charts provide key insights into consolidation ratios that can be achieved practically. The VDI was easily able to scale-up to 45 virtual desktops (using Windows 7 machines). At the threshold limit, the server CPU utilization was only near 50% while memory became a bottleneck. 8
Figure 4: Host CPU Performance Chart Figure 5: Host Memory Performance Chart 9
These results indicate that a physical server with 8GB Memory and 8 CPU cores can host around 45 virtual desktops. Assuming an average PC power consumption of 190 Watts and an average 8 core CPU power consumption of 450 Watts, the amount of power savings for 1 to 10000 virtual desktops is highlighted in Figure 6. Figure 6: Power Savings in Virtual Desktops As per calculations, the amount of power savings for 10000 desktops can be a significant 16 GWh per year. The high-level assumptions for these calculations are: n n n n n n Average Cooling Power Required = Average Power Consumed Average PC Power Consumption = 450 W Average Thin Client Power Consumption = 50 W Average Server Power Consumption = 450 W Average Storage Power Consumption = 1000 W per TB Average hard disk size in traditional desktop = 150 GB 10
If we plot these metrics on a chart, it can be observed from the calculations that the amount of savings increases as the number of virtual desktops increase. So, the organic growth for an organization can, in fact, lead to additional savings on power and cooling without compromising the end-users desktop experience. Figure 7: Annual Power Saving Metrics If we analyze the environmental impact of the power savings achieved through desktop virtualization, significant contribution towards the environment is evident from the metrics and charts in Figures 8 and 9. These metrics are under the assumption that every kwh of power emits 0.6 kg of carbon dioxide (CO2) and on an average 202 kg of CO2 is absorbed by a single tree. 11
Figure 8: Annual CO2 Emission Reductions Metrics Figure 9: CO2 Emission Reduction Equivalent by Planting Trees 12
Conclusion The proliferation of desktops and the escalating desktop management costs are a cause for concern for several organizations. Power and cooling costs, often ignored by organizations, are significant contributors to the escalating costs of desktop ownership. Power and cooling cost savings that were once part of Green IT initiatives are now regarded as strategic cost control initiatives. The traditional green desktops only offer power management techniques and are a limited contribution to Green IT initiatives by hardware OEMs. Virtualization is an effective technique to reduce the overall cost of ownership as well as the carbon footprint of an organization. This technique has often been confined to servers alone while desktops have been excluded from this organizational initiative. Desktop virtualization is the mechanism of transforming desktops from distributed silos to a centralized pool of virtual resources hosted within the secure premises of the datacenter. This has inherent operational benefits and also brings in the added advantage of reduced power and cooling costs for the desktop infrastructure. From the results of tests conducted in our lab, it was observed that high consolidation ratios of virtual desktops on physical servers can result in huge power savings and help in effectively reducing operational costs and the overall carbon footprint of an organization. References [1] Green Grid, http://www.thegreengrid.org/ [2] VMware, http://www.vmware.com [3] Wikipedia, www.wikipedia.org [4] TCS NetApp Solutions Lab PoC Reports [5]TCS VDI Brochure Vmware is a registered trademark of VMware Inc. Dell is a registered trademark of Dell Inc. NetApp is a registered trademark of NetApp Inc. 13
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