VDI Validation Guide—VMware Horizon on VxRail and vSAN Ready Nodes
Login VSI test results and analysis
Login VSI test results and analysis
-
Summary of test results
The following table summarizes the host utilization metrics for the different Login VSI workloads that we tested and the user density derived from Login VSI performance testing:
Table 7. Login VSI test results summary Server configuration Login VSI workload Operating system User density Average CPU 1 Average GPU Average active memory Average IOPS per user Average network Mbps per user Density Optimized Knowledge Worker Windows 10, 1803 130 86% N/A 140 GB 15.9 1.55 Mbps Density Optimized Knowledge Worker Windows 10, 1909 125 85% N/A 134 GB 7.49 1.52 Mbps Density Optimized Power Worker Windows 10, 1909 100 87% N/A 154 GB 8.45 2.31 Mbps Density Optimized + 6 x T4 Multimedia Worker (T4-2B vGPU) Windows 10, 1909 48 80% 22% 392 GB 16 21 Mbps As shown in the table, the CPU was the bottleneck in all the test cases. In all but the Multimedia Worker test, the CPU utilization metric reached the 85 percent (+5 percent margin) threshold that we set for CPU utilization. These threshold values, as shown in Table 4, are carefully selected to deliver an optimal combination of excellent EUE and cost-per user while also providing burst capacity for seasonal or intermittent spikes in usage. We do not load the system beyond these thresholds to reach a Login VSImax (Login VSImax shows the number of sessions that can be active on a system before the system is saturated).
Memory was not a constraint during testing. The total memory of 768 GB was enough for all of the Login VSI workloads to run without any constraints. With a dual-port 25 GbE NIC available on the hosts, network bandwidth was also not an issue. Disk latency was also under the threshold that we set, and disk performance was good.
For the multimedia workload test, the maximum number of users that can be accommodated on the host with each having an NVIDIA T4-2B vGPU profile is 48. The total available frame-buffer on the host with six NVIDIA T4 GPUs configured is 96 GB. The Login VSI scores and host metric results indicate that user experience and performance were good during the running of this graphics-intensive workload.
We have recommended the user densities based on the Login VSI test results and considering the thresholds that we set for host utilization parameters. To maintain good EUE, do not exceed these thresholds. You can load more user sessions and exceed these thresholds, but you might experience a degradation in user experience.
The host utilization metrics mentioned in the table are defined as follows:
- 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.
1 The Ready Solutions for VDI team recommends that average CPU utilization not exceed 85 percent in a production environment. A 5 percent margin of error was allocated for this validation effort. Therefore, CPU utilization sometimes exceeds our recommended percentage. Because of the nature of Login VSI testing, these exceptions are reasonable for determining our sizing guidance.Knowledge Worker, 510 users, ESXi 6.7u3, Horizon 7.10, Windows 1803
We performed this test with the Login VSI Knowledge Worker workload. The test was performed on a 4-node VxRail cluster. We created the desktops VMs using VMware Horizon instant clone technology. We used the VMware Horizon Blast Extreme display protocol. Host 1 hosted both management and desktop VMs. We populated the compute hosts with 130 desktop VMs each and the management host with 120 desktop VMs.
CPU usage
The following graphs show the CPU utilization across the four hosts during the testing. CPU usage with all VMs powered on was approximately 10 percent before the test started. The CPU usage steadily increased during the login phase, as shown in Figure 2.
Figure 2. CPU usage 
During the steady state phase, an average CPU utilization of 86 percent was recorded. This value is close to the pass/fail threshold that we set for average CPU utilization (see Table 4). To maintain good EUE, do not exceed this threshold. You can load more user sessions while exceeding this threshold for CPU, but you might experience a degradation in user experience.
As shown in Figure 3, the CPU readiness was well below the 5 percent threshold that we set. The average steady state CPU core utilization across the four hosts was 75 percent, as shown in Figure 4.
Figure 3. CPU readiness 
Figure 4. CPU core utilization 
Memory
We observed no memory constraints during the testing on either the management or compute hosts. Out of 768 GB of available memory per node, the compute host reached a maximum consumed memory of 581 GB and a steady state average of 531 GB. Active memory usage reached a maximum active memory of 326 GB and recorded a steady state average memory of 140 GB. There was no memory ballooning or swapping on the hosts.
Figure 5. Consumed memory usage 
Figure 6. Active memory usage 
Network usage
Network bandwidth was not an issue during the testing. The network usage recorded a steady state average of 792 Mbps. The busiest period for network traffic was during the logout phase when a peak value of 5,852 Mbps was recorded. The average steady state network usage per user was 1.55 Mbps.
Figure 7. Network usage 
Cluster IOPS
Cluster IOPS reached a maximum value of 17,368 for read IOPS and 5,152 for write IOPS during the steady state phase. The average steady state read and write IOPS were 5,362 and 2,749 respectively. The average disk IOPS (read+write) per user was 15.9.
Figure 8. Cluster IOPS 
Disk I/O latency
Cluster disk latency reached a maximum read latency of 0.12 milliseconds and a maximum write latency of 0.2 milliseconds during the logout phase. The average steady state read latency was 0.25 milliseconds, and the average steady state write latency was 0.83 milliseconds.
Figure 9. Disk latency 
User experience
The baseline score for the Login VSI test was 835. This score falls in the 800 to 1,199 range rated as "Good" by Login VSI. For more information about Login VSI baseline ratings and baseline calculations, see this Login VSImax article. We ran the Login VSI test for 510 user sessions for the Knowledge Worker workload. As indicated by the blue line in Figure 10, the system reached a VSImax average score of 1,259 when 510 sessions were loaded. This value is well below the VSI threshold score of 1,836 set by the Login VSI tool. During the testing, VSImax was never reached, which typically indicates a stable system and a better user experience.
The Login VSImax user experience score for this test was not reached. When manually interacting with the sessions during the steady state phase, the mouse and window movement were responsive, and video playback was good. No "stuck sessions" were reported during the testing, indicating that the system was not overloaded at any point. See Appendix A, which explains the Login VSI metrics
Figure 10. Login VSI graph 
Table 8. Login VSI score summary Login VSI baseline VSI index average VSIMax reached VSI threshold 835 1,259 No 1,836 Knowledge Worker, 485 users, ESXi 6.7u3, Horizon 7.10, Windows 1909
We performed this test with the Login VSI Knowledge Worker workload. The test was performed on a 4-node VxRail cluster. We created the desktop VMs using VMware Horizon instant clone technology. Host 1 hosted both management and desktop VMs. We populated each compute host with 125 desktop VMs and the management host with 110 desktop VMs. We used the VMware Horizon Blast Extreme display protocol.
CPU usage
The following graphs show the CPU utilization across the four hosts during the testing. CPU usage with all VMs powered on was approximately 7 percent before the test started. The CPU usage steadily increased during the login phase. During the steady state phase, an average CPU utilization of 85 percent was recorded. This value is close to the pass/fail threshold that we set for average CPU utilization (see Table 4). To maintain good EUE, do not exceed this threshold. You can load more user sessions while exceeding this threshold, but you might experience a degradation in user experience.
Figure 11. CPU usage 
As shown in Figure 12, the CPU readiness was well below the 5 percent threshold that we set.
Figure 12. CPU readiness 
The average steady state CPU core utilization across the four hosts was 75 percent, as shown in Figure 13.
Figure 13. CPU core utilization 
Memory
We observed no memory constraints during the testing on either the management or compute hosts. Out of 768 GB of available memory per node, the compute host reached a maximum consumed memory of 550 GB and a steady state average of 529 GB. Active memory usage reached a maximum of 293 GB and recorded a steady state average memory of 134 GB. There was no memory ballooning or swapping on the hosts.
Active memory utilization was reduced to a minimum when users logged out of their sessions. There was an increase in active memory usage during the re-create phase. This peak in active memory usage is expected during the instant clone re-creation process because all VMs that have been destroyed after user logout have to be re-created, which is a memory-intensive task.
Figure 14. Consumed memory usage 
Figure 15. Active memory usage 
Network usage
Network bandwidth was not an issue on this test. A steady state average of 740 Mbps was recorded. The busiest period for network traffic was during the steady state phase. Compute host 2 recorded a peak network usage of 2,662 Mbps. The average steady state network usage per user was 1.52 Mbps.
Figure 16. Network usage 
Cluster IOPS
Cluster IOPS reached a maximum read value of 13,462, and it reached a maximum write value of 2,787 in the logout phase. The average steady state read and write IOPS were 1,247 and 2,389, respectively. The average disk IOPS per user during the steady state period was 7.49.
Figure 17. Cluster IOPS 
Disk latency
Cluster disk latency reached a maximum read latency value of 0.69 milliseconds, and it reached and a maximum write latency value of 1.89 milliseconds during the logout phase. The average steady state read latency was 0.24 milliseconds, and the average steady state write latency was 0.67 milliseconds.
Figure 18. Disk latency 
User experience
The baseline score for the Login VSI test was 938. This score falls in the 800 to 1,199 range rated as "Good" by Login VSI. For more information about Login VSI baseline ratings and baseline calculations, see this Login VSImax article. We ran the Login VSI test for 485 user sessions for the Knowledge Worker workload. As indicated by the blue line in Figure 19, the system reached a VSImax average score of 1,289 when 485 sessions were loaded. This value is well below the VSI threshold score of 1,938 set by the Login VSI tool. During the testing, VSImax was never reached, which normally indicates a stable system and a better user experience.
When manually interacting with the sessions during the steady state, the mouse and window movements were responsive, and video playback was good. No "stuck sessions" were reported during the testing, indicating that the system was not overloaded at any point. See Appendix A, which explains the Login VSI metrics.
Figure 19. Login VSI graph 
Table 9. Login VSI score summary Login VSI baseline VSI index average VSIMax reached VSI threshold 938 1,289 No 1,938 Power Worker, 385 users, ESXi 6.7u3, Horizon 7.10, Windows 1909
We performed this test with the Login VSI Power Worker workload. The test was performed on a 4-node VxRail cluster. We created the desktop VMs using VMware Horizon instant clone technology. We used the VMware Horizon Blast Extreme display protocol. Host 1 was provisioned with both management and desktop VMs. We populated the compute host with 100 desktop VMs and the management host with 85 desktop VMs.
CPU usage
The following graphs show the CPU utilization across the four hosts during the testing. CPU usage with all VMs powered on was approximately 10 percent before the test started. The CPU usage steadily increased during the login phase. During steady state, an average CPU utilization of 87 percent was recorded. This value is close to the pass/fail threshold that we set for average CPU utilization (see Table 4). For good EUE, do not exceed this threshold. You can load more user sessions while exceeding this threshold for CPU, but you might experience a degradation in user experience.
As shown in Figure 21, the CPU readiness was well below the 5 percent threshold that we set. The average steady state CPU core utilization across the four hosts was 79 percent, as shown in Figure 22.
Figure 20. CPU usage 
Figure 21. CPU readiness 
Figure 22. CPU core utilization 
Memory
We observed no memory constraints during the testing on either the management or compute hosts. Out of 768 GB of available memory per node, the compute host reached a maximum consumed memory of 741 GB and a steady state average of 691 GB. Active memory usage reached a maximum of 459 GB and recorded a steady state average memory of 154 GB. There was no memory ballooning or swapping on the hosts.
Active memory utilization was reduced to a minimum when users logged out of their sessions. There was an increase in active memory usage during the re-create phase. This peak in active memory usage is expected during the instant clone re-creation process because all VMs destroyed after user logout have to be re-created, which is a memory-intensive task.
Figure 23. Consumed memory usage 
Figure 24. Active memory usage 
Network usage
Network bandwidth was not an issue on this test. A steady state average of 891 Mbps was recorded. The busiest period for network traffic was toward the end of the logout phase and during the starting of the re-creation of instant clones. Compute host 3 reached a peak value of 3,769 Mbps toward the end of the logout phase.
Figure 25. Network usage 
IOPS
As shown in the following figure, the cluster IOPS reached a maximum read value of 21,090 in the re-create phase. It reached a maximum write value of 6,283 toward the end of the logout phase. The average steady state read and write IOPS were 1,310 and 1,941, respectively. The average disk IOPS per user during the steady state period was 8.45.
Figure 26. IOPS 
Disk latency
As shown in the following figure, cluster disk latency reached a maximum read value of 12.83 milliseconds, and it reached a maximum write value of 3.12 milliseconds during the logout phase. The average steady state read latency was 0.77 milliseconds, and the average steady state write latency was 3.80.
Figure 27. Disk latency 
User experience
The baseline score for the Login VSI test was 877. This score falls within the 800 to 1,199 range rated as "Good" by Login VSI. For more information about Login VSI baseline ratings and baseline calculations, see this Login VSImax article. We ran the Login VSI test for 385 user sessions for the Power Worker workload. As indicated by the blue line in the following figure, the system reached a VSImax average score of 1,271 when 385 sessions were loaded. This score is well below the VSI threshold score of 1,878 set by the Login VSI tool. During the duration of testing, VSImax was never reached, which normally indicates a stable system and a better user experience.
When manually interacting with the sessions during the steady state phase, the mouse and window movement were responsive, and video playback was good. There was only one "stuck session" reported during the testing, indicating that the system was not overloaded at any point in time. See Appendix A, which explains the Login VSI metrics.
Figure 28. Login VSI graph 
Table 10. Login VSI score summary Login VSI baseline VSI index average VSImax reached VSI threshold 877 1,271 No 1,878 Multimedia Worker, 48 users, ESXi 6.7u3, Horizon 7.10, Windows 1909
We performed this test with the Login VSI Multimedia Worker workload. The test was performed on the compute host 4 by configuring six NVIDIA T4 GPUs. We provisioned the host with 48 vGPU-enabled VMs, and each of the desktop VMs used the NVIDIA T4-2B vGPU profile. The infrastructure VMs were run on the management host 1. The desktop VMs were created using VMware Horizon instant clone technology. We used the VMware Horizon Blast Extreme display protocol for this testing. Hosts 2 and 3 did not have any load.
CPU usage
The following graph shows the CPU utilization on the GPU-enabled compute host during the testing. CPU usage with all virtual machines powered on the host was approximately 4 percent before the test started. The CPU usage steadily increased during the login phase, as shown in the following figure. During steady state, an average CPU utilization of 80 percent was recorded. This value was below the pass/fail threshold that we set for average steady state CPU utilization (see Table 4).
Figure 29. CPU usage 
As shown in the following figure, the CPU readiness was well below the 5 percent threshold that we set. The average steady state CPU core utilization across the four hosts was 72 percent, as shown in Figure 31.
Figure 30. CPU readiness 
Figure 31. CPU core utilization 
GPU
The following graph shows the GPU usage across the six NVIDIA T4 GPUs configured on the host. The GPU usage during the steady state period across the six GPUs averaged approximately 22 percent. A peak GPU usage of 36 percent was recorded on GPU 3 during the logout phase.
Figure 32. GPU usage 
Memory
We observed no memory constraints during the testing on either the management or compute hosts. Out of 768 GB of available memory per node, the compute host reached a maximum consumed memory of 440 GB and a maximum active memory of 392 GB during the steady state phase. There were no variations in memory usage throughout the test because all vGPU-enabled VM memory was reserved. There was no memory ballooning or swapping on the hosts.
Figure 33. Consumed memory usage 
Figure 34. Active memory usage 
Network usage
Network bandwidth was not an issue during the test. A steady state peak value of 1,448 Mbps was recorded on the GPU-enabled compute host. The busiest period for network traffic was during the steady state phase. The steady state average network usage value was 1,009 Mbps. The average network usage per user was 21 Mbps.
Figure 35. Network usage 
IOPS
As shown in the following figure, the cluster IOPS reached a maximum value of 616 for read IOPS during the login phase and 938 for write IOPS during the steady state phase of the testing. The average steady state value for read IOPS was 228, and the average steady state value for write IOPS it was 542. The average disk IOPS (read and write) per user was 16.
Figure 36. IOPS 
Disk latency
Cluster disk latency reached a maximum read latency value of 0.6 milliseconds and it reached a maximum write latency value of 0.9 milliseconds during the logout phase. An average read latency of 0.38 milliseconds, and an average write latency of 0.7 milliseconds were recorded during the steady state phase.
Figure 37. Disk latency 
User experience
The baseline score for the Login VSI test was 877. This score falls within the 800 to 1,199 range rated as "Good" by Login VSI. For more information about Login VSI baseline ratings and baseline calculations, see this Login VSImax article. We ran the Login VSI test for 48 user sessions for the Login VSI Multimedia Worker workload. As indicated by the blue line in the following figure, the system reached a VSImax average score of 1,223 when 48 sessions were loaded. This is well below the VSI threshold score of 1,877 set by the Login VSI tool. During the duration of testing, VSImax was never reached, which normally indicates a stable system and a better user experience.
The Login VSImax user experience score for this test was not reached. When manually interacting with the sessions during steady state, the mouse and window movements were responsive, and video playback was good. There were no "stuck sessions" recorded during the testing, indicating that the system was not overloaded at any point. See Appendix A for details of the Login VSI metrics.
Figure 38. Login VSI graph 
Table 11. Login VSI summary Login VSI baseline VSI index average VSImax reached VSI threshold 877 1,223 No 1,877