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DELL Virtual Desktop Infrastructure Study

END-TO-END COMPUTING Dell │ Enterprise Solutions Engineering

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THIS WHITE PAPER  IS FOR  INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL  INACCURACIES. THE CONTENT  IS PROVIDED AS  IS, WITHOUT EXPRESS OR  IMPLIED WARRANTIES OF ANY KIND. 

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Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products. Dell disclaims proprietary interest in the marks and names of others. 

©Copyright 2008 Dell Inc. All rights reserved. Reproduction in any manner whatsoever without the express written permission of Dell Inc. is strictly forbidden. For more information, contact Dell. 

Information in this document is subject to change without notice. 

 

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Table of Contents

Abstract: Dell Virtual Remote Desktop – Infrastructure Sizing Study ........................................................... 5 

Introduction .................................................................................................................................................. 5 

1.0 Dell’s VRD Solution .............................................................................................................................. 5 

2.0 Infrastructure Sizing Summary ............................................................................................................ 6 

3.0 Experimental Setup and Workload Design ......................................................................................... 7 

3.1 Server and Storage Hardware: ........................................................................................................ 8 

3.2  Desktop Virtual Machine Configuration: ....................................................................................... 8 

4.0 Performance Results ........................................................................................................................... 9 

4.1 High Performance User ................................................................................................................... 9 

4.2 Knowledge Worker ....................................................................................................................... 10 

4.3 Structured Task Worker ................................................................................................................ 12 

5.0 Summary and Suggested Guidelines ................................................................................................. 13 

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Dell Virtual Remote Desktop – Infrastructure Sizing Study End-to-End Computing

Enterprise Solutions Engineering Dell Inc.

Introduction The Virtual Remote Desktop (VRD) solution that uses Dell™ hardware with the VMware® Virtual Desktop Infrastructure (VDI) application is the second offering from Dell in the flexible computing space. The Dell VRD solution addresses the need of customers who require alternate desktop architectures. In a VRD infrastructure, the user applications, data, and images are maintained by a data center administrator. Each desktop instance is run inside a Virtual Machine (VM) running on Dell PowerEdge™ servers running VMware ESX virtualization software. This white paper describes the sizing guidelines for configuring the backend infrastructure (ESX servers in particular) for a Dell VRD solution.

1.0 Dell VRD Solution  The Dell VRD solution is built on Dell hardware and VMware VI3 and Virtual Desktop Manager (VDM) applications. The components of this solution using Microsoft® Active Directory® (AD) servers are shown in Figure 1. Enterprise desktops are hosted on VMware infrastructure and accessed by remote users through the VDM connection server. VDM connection server handles both the creation/provisioning of desktop VMs and the user connections to those VMs. The VMs run in a resource-isolated, secure environment and support both Microsoft® Windows® XP and Windows Vista® 32-bit operating systems.

AD authentication is performed when the user enters login information and password through the web access or VDM client. User policies and assignments are handled by the VDM server by polling the Microsoft® AD server for user and group information to assign the appropriate VM. After passing authentication, the user’s AD credentials are passed through to the target VM and an RDP connection is established. This solution provides Dell IT customers with centralized control over desktop computing resources and their data by hosting

Figure 1: Active Directory (AD) VRD Solution 

 

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1. Start a PowerPoint® application. Open a 5-MB presentation with automation and go through 50 slides. Close the PowerPoint application.

2. Start an Internet Explorer® application. Browse three different web pages. Close the Internet Explorer application.

3. Start a command prompt and perform a directory listing. Close the command prompt.

4. Start a PowerPoint application. Open a 5-MB presentation with automation and go through 50 slides. Close the PowerPoint application.

5. Start an Excel® application. Open an Excel file. Close the Excel application. 6. Start a PowerPoint application. Open a 5-MB presentation with automation and go

through 50 slides. Close the PowerPoint application. 7. Start a Microsoft Word® application. Type a one-page document. Close the Microsoft

Word application. Performing a single iteration of these operations took approximately 5-7 minutes depending on the typing speed used. Typing speeds of 120 wpm and 200 wpm were used to gather multiple data points. The typical typing speed for experts is in the 60-75 wpm range, and therefore these results represent a worst-case scenario for most customers. The BAPCO® SYSmark® 2007 performance metric application was used to represent a performance user and also to enable comparisons to customers with existing client hardware. Simple data entry tasks were performed to simulate a structured task worker. In addition, the AutoIT executable runs within the desktop VM and there is no interaction with external clients. Therefore, there is no end-user latency that is measured for this study and all the measurements are performed at the ESX server hosting the desktop VMs.

3.1 Server and Storage Hardware: • Dell PowerEdge R805 (AMD® Opteron® Processor 2222 3.0GHz, 16GB DDR2-667)

o Software – ESX Server 3i 3.5.0 build-62774 • Dell PowerEdge 2950 (Intel® Processor E5345 2.8GHz, 32GB DDR2-667)

o Software – ESX Server 3i 3.5.0 build-62774 • Dell PowerVault® MD3000 (15 x 146GB 15k RPM RAID-5 Array)

3.2  Desktop Virtual Machine Configuration: • XP Desktop

Single Virtual CPU, 384MB Memory, 10GB virtual disk Windows XP Professional with SP2

• Windows Vista Desktop Single Virtual CPU, 1024MB Memory, 30GB virtual disk Windows Vista Business Edition

 

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Figure 8: CPU Usage and Memory Usage for Structured Task Worker Scenario 

The average CPU usage when running 16 VMs (four VMs per CPU core) is 15% and the system memory used is approximately 5.5GB. As the desktops are running, more system memory is made available to the system due to transparent page sharing by the ESX server that frees up to 12GB while 16 desktop VMs are running the data entry workload. At 7:41, 16 additional VMs are powered on (from suspend mode), whichresults in a CPU usage spike of up to 60%. Once all the VMs are powered on, the average CPU usage, when running the structured task worker on 32 concurrent VMs, increases to 31% and available system memory drops to 8GB during the run period for 32 VMs.

After 20 minutes at 8:02, an additional 16 VMs are powered on and the workload runs on 48 desktop VMs, which increases the average CPU usage to 61% and drops the available system memory to 2.4GB. The CPU usage almost spikes to 100% when the final 16 VMs are powered on while running 48 VMs. When the workload runs on the remaining 16 VMs (increasing the total desktop VMs running to 64), the average CPU usage increases to 79% and available memory is as low as 1.8GB during this period. The CPU usage volatility is more pronounced during the 48 and 64 desktop VM runs since the scheduling overhead on the ESX server is extremely high due to the large number of VMs.

5.0 Summary and Suggested Guidelines Figure 9 shows the range of desktop virtual machines that were hosted on the PowerEdge R805 based on the workload profile used in this study. For a high-performance user, there was a negative impact on overall performance when more than four VMs were running on the server.

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Figure 9: Recommended Desktop Virtual Machines Based on Available CPU Cores 

For a knowledge worker scenario, running 24 to 32 VMs resulted in about 85% of CPU usage and no degradation in end-user performance. For a structured task worker scenario, up to 64 VMs were hosted on a single server with no negative impact to desktop-user performance. When performing capacity planning for a VDI deployment, the end-user workload will have a large impact on the number of ESX servers required to host the remote desktop images inside the data center. Similar analysis needs to be conducted using a representative desktop workload of the users supported by the Virtual Remote Desktop solution.