Table of Contents
Advertisement
Estimating CPU Requirements for Virtual Desktops
When estimating CPU, you must gather information about the average CPU utilization for various types of
workers in your enterprise. In addition, calculate that another 10 to 25 percent of processing power is required
for virtualization overhead and peak periods of usage.
N
This topic addresses issues regarding CPU requirements when accessing View desktops remotely. If
OTE
users run a View desktop in local mode on their client systems, the View desktop uses the available CPUs on
the client device, up to 2 CPUs.
CPU requirements vary by worker type. During your pilot phase, use a performance monitoring tool, such as
Perfmon in the virtual machine and ESX Top in ESX, to understand both the average and peak CPU use levels
for these groups of workers. Also use the following guidelines:
Software developers or other power uses with high-performance needs might have much higher CPU
n
requirements than knowledge workers and task workers. Dual virtual CPUs are recommended for
compute-intensive tasks or for Windows 7 desktops that need to play 720p video using the PCoIP display
protocol.
Single virtual CPUs are generally recommended for other cases.
n
Because many virtual machines run on one server, CPU can spike if agents such as antivirus agents all check
for updates at exactly the same time. Determine which agents and how many agents could cause performance
issues and adopt a strategy for addressing these issues. For example, the following strategies might be helpful
in your enterprise:
Use View Composer to update images rather than having software management agents download
n
software updates to each individual virtual desktop.
Schedule antivirus and software updates to run at nonpeak hours, when few users are likely to be logged
n
in.
Stagger or randomize when updates occur.
n
As an informal initial sizing approach, to start, assume that each virtual machine requires 1/8 to 1/16 of a CPU
core as the minimum guaranteed compute power. That is, plan a pilot that uses 8 to 16 virtual machines per
core. For example, if you assume 16 virtual machines per core and have a 2-socket quad-core ESX server, you
can host 128 virtual machines on the server during the pilot. Monitor the overall CPU usage on the host during
this period and ensure that it rarely exceeds a safety margin such as 80 percent to give enough headroom for
spikes.
Choosing the Appropriate System Disk Size
When allocating disk space, provide only enough space for the operating system, applications, and additional
content that users might install or generate. Usually this amount is smaller than the size of the disk that is
included on a physical PC.
Because datacenter disk space usually costs more per gigabyte than desktop or laptop disk space in a traditional
PC deployment, optimize the operating system image size. The following suggestions might help optimize
image size:
Remove unnecessary files. For example, reduce the quotas on temporary Internet files.
n
Choose a virtual disk size that is sufficient to allow for future growth, but is not unrealistically large.
n
Use centralized file shares or a View Composer persistent disk for user-generated content and user-
n
installed applications.
VMware, Inc.
Chapter 4 Architecture Design Elements and Planning Guidelines
33
Advertisement
Table of Contents
