Overview

The Dell VDI Solutions team carries out performance analysis and characterization (PAAC) on Dell VDI solutions to ensure the optimal combination of end-user experience (EUE) and cost-per-user. The team uses a carefully designed, holistic methodology that monitors both hardware resource utilization parameters and EUE during load-testing.

Login Enterprise performance testing

Process and monitoring

Each user load was tested against four runs: a pilot run to validate that the infrastructure was performing properly (and that valid data could be captured), and three subsequent runs to enable data correlation.

During testing, while the environment was under load, the Dell VDI Solutions team logged in to a session and completed tasks that correspond to the user workload. Although this test is subjective, it helps to provide a better understanding of the EUE in the desktop sessions, particularly under high load. This test also helps to ensure reliable data gathering.

The team monitored the following resources to ensure that the user experience was not compromised:

• Compute host servers—Solutions based on VMware vCenter for VMware vSphere gather key data (CPU, memory, disk, and network usage) from each of the compute hosts during each test run. This data is exported to .csv files for single hosts and then consolidated to show data from all hosts. While the report does not include specific performance metrics for the management host servers, these servers are monitored during testing to ensure that they are performing at an expected level with no bottlenecks.
• Hardware resources—Resource overutilization can cause poor EUE. Relevant resource utilization parameters were monitored and compared to relatively conservative thresholds. As shown in the following table, the thresholds were selected based on industry best practices and Dell VDI experience to provide an optimal trade-off between good EUE and cost-per-user, while also allowing sufficient burst capacity for seasonal or intermittent spikes in demand.

Table 3.      Login Enterprise test thresholds

Note: The Dell VDI Solutions team recommends that the average CPU utilization does not exceed 85 percent in a production environment. A five percent margin of error was allocated for this validation effort. CPU utilization sometimes exceeds Dell’s recommended percentage, but because of the nature of PAAC testing, these exceptions are reasonable for determining Dell’s sizing guidance.

Load generation

Login Enterprise installs a standard collection of desktop application software, including Microsoft Office and Adobe Acrobat Reader, on each VDI desktop testing instance. It then uses a configurable launcher system to connect a specified number of simulated users to available desktops within the environment. When the simulated user is connected, a login script configures the user environment and starts a defined workload. Each launcher system can launch connections to several VDI desktops (target machines). A centralized management console configures and manages the launchers and the Login Enterprise environment.

The team used the following login and boot conditions:

• Users were logged in within a login timeframe of 1 hour
• All desktops were started before users were logged in

Login Enterprise workloads

The following table describes the Login Enterprise workloads that the team used in testing:

Table 4.      Profile and workload

Software versions

The following tables summarizes the software versions that the team used to test the Login Enterprise workloads:

Table 5.      Software versions

Desktop VM test configurations

The following table summarizes the desktop VM configurations that the team used to test for the Login VSI workloads:

Table 6.      Desktop VM test configurations

Results summary

The following table summarizes the host utilization metrics that the team observed for the different Login Enterprise workloads tested, as well as the user density that they derived from Login Enterprise performance testing:

Table 7.      Test results summary

The host utilization metrics in the preceding table are defined as:

• User density—The number of users per compute host that successfully completed the workload test within the acceptable resource limits for the host. For clusters, this number reflects the average of the density achieved for all compute hosts in the cluster.
• Average CPU—The average CPU usage over the steady-state period. For clusters, this number represents the combined average CPU usage of all compute hosts. On the latest Intel processors, the ESXi host CPU metrics exceed the rated 100 percent for the host if Turbo Boost is enabled, which is the default setting. An additional 35 percent of CPU is available from the Turbo Boost feature, but this additional CPU headroom is not reflected in the VMware vSphere metrics where the performance data is gathered.
• Average active memory—For ESXi hosts, the amount of memory that is actively used, as estimated by the VMkernel based on recently touched memory pages. For clusters, this is the average amount of physical guest memory that is actively used across all compute hosts over the steady-state period.
• Average IOPS per user—IOPS calculated from the average cluster disk IOPS over the steady-state period divided by the number of users.
• Average network usage per user—Average network usage on all hosts calculated over the steady-state period divided by the number of users.