Search the VMware Knowledge Base (KB)
View by Article ID

vSAN performance diagnostics (2148770)

  • 0 Ratings


vSAN performance diagnostics provides feedback on how to extract the best performance in a given vSAN cluster. It consumes the data available via the vSAN performance service in vSAN health and provides details on performance issues seen in the VSAN cluster. To use vSAN performance diagnostics, you must join the Customer Experience Improvement Program (CEIP), and enable vSAN Performance Service.

vSAN performance diagnostics requires the following user inputs.
  1. Goal: This defines the context or user perspective of the performance evaluation. You should choose the desired evaluation type; that is, whether it is for maximum I/Os per second (Max IOPS), maximum throughput (Max Throughput), or minimum latency (Min Latency). Please remember that these evaluations may yield different results. As an example, the requirements for maximum IOPS are different than the requirements for minimum latency. The goal may be set to “Max IOPS”, “Max Throughput”, or “Min Latency”. The diagnostics evaluation will assume the selected objective for the analysis. 
  2. Time Range: This specifies the time duration for which vSAN performance diagnostics is required. The default time range is the last 1 hour. You can also increase it to the last 24 hours, or choose a custom time interval during the last 90 days. In case a vSAN proactive benchmark has been experimented with on this cluster, the time ranges for the proactive experiments will appear in the drop-down menu. Similarly, when HCIBench v1.6.2 is used to benchmark the cluster, the time range during which HCIBench was run will appear in the drop-down menu. If you are running some other benchmark, please make sure to run the benchmark for at least one hour, and then choose the start time of the benchmark and the duration (number of hours for which the benchmark was run). Performance diagnostics will not report any performance issues for an idle cluster. Instead, an issue mentioning: “No benchmark is seen to be running during the queried period”will be listed for an idle cluster.


After you click the Submit button, performance data for the specified time interval is transmitted to the analytics backend system. All data is obfuscated, compressed, and transmitted over the HTTPS protocol. After the data has been processed, the screen returns with a list of issues (or a message that no issues are found), and an Ask VMware link that documents how to find a solution for the issue. With each issue, there is an issue description that describes what the issue is about in a small paragraph. Each issue is accompanied with supporting data, which helps you understand and debug the performance issue. The supporting data is usually in the form of performance graphs showing the entity, and metrics which explain the root cause behind why a performance issue was triggered. The graph shows data along with a threshold that indicates at which points in time the threshold was not met.

Possible issues, listed performance graphs, and possible remedies include:

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


  • 0 Ratings

Did this article help you?
This article resolved my issue.
This article did not resolve my issue.
This article helped but additional information was required to resolve my issue.

What can we do to improve this information? (4000 or fewer characters)

Please enter the Captcha code before clicking Submit.
  • 0 Ratings