VDI benchmarking is hard. What makes it challenging is getting a good representation or simulation of VDI users. If we closely look at typical office users, we can get a spectrum of VDI users where at the one end of spectrum, the user may be using some simple Microsoft Office applications at a relatively moderate speed, whereas at the other end of spectrum, the user may be running some CPU-heavy multimedia applications and switching between many applications much faster. We classify the fast user as the power user or the “heavy” user, whereas we classify the user at the other end of the spectrum as the task worker or as the “light” user. In between the two categories, we define one more category which lies in between these two ends of the spectrum, which is the “medium” user.
To simulate these different categories of users and to make the job of VDI benchmarking much easier, we have made VMware View Planner 3.0, which simulates a workload representative of many user-initiated operations that take place in a typical VDI environment. The tool simulates typical Office user applications such as PowerPoint, Outlook, and Word; and Adobe Reader, Internet Explorer Web browser, multimedia applications, and so on. The tool can be downloaded from: http://www.vmware.com/products/desktop_virtualization/view-planner/overview.html.
If we look at the three categories of VDI users outlined above, one of the main differentiating factors across this gamut of VDI users is how fast they act and this is simulated using the concept of “think time” in the View Planner tool. The tool uses the thinktime parameter to randomly sleep before starting the next application operation. For the heavy user, the value of thinktime is kept very low at 2 seconds. This means that operations are happening very fast and users are switching across different applications or doing operations in an application every 2 seconds on average. The View Planner 3.0 benchmark defines a score, called “VDImark” which is based on this “heavy” user workload profile. For a medium user, the think time is set to 5 seconds, and for a light user, the think time is set to 10 seconds. The heavy VDI user also uses a bigger screen resolution compared to the medium or light user. The simulation of these category of users in the View Planner tool is summarized in the table below:
In order to show the capability of View Planner 3.0 to determine the sizing for VDI user VMs per host, we ran a flexible mode of View Planner 3.0, which allowed us to create medium and light user workloads (the heavy workload profile pre-exists), as well to understand the user density for different types of VDI users for a given system. The flexible mode will be available soon through Professional Services Organization (PSO) and to selected partners.
The experimental setup we used to compare these different user profiles is shown below:
In this test, we want to determine how many VMs can be run on the system while each VM is performing its heavy, medium, or light user profiles. In order to do this, we need to set a baseline of acceptable performance, which is defined by the quality of service (QoS) as defined in the View Planner user guide. The number of VMs that passed the QoS score is shown in the chart below.
The chart shows that we can run about 53 VMs for the heavy user (VDImark), 67 VMs for the medium user, and 91 VMs for light users. So, we could consolidate about 25% more desktops if we used this system to host users with medium workloads instead of heavy workloads. And we could consolidate 35% more desktops if we used this system to host users with light workloads instead of medium workloads. So, it is crucial to fully specify the user profile whenever we talk about the user density.
In this blog, we demonstrated how we used the View Planner 3.0 flexible mode to run different user profiles and to understand the user density for a system under test. If you have any questions and want to know more about View Planner, you can reach out to the team at firstname.lastname@example.org