You can use I/O trip analyzer to diagnose the virtual machine I/O latency issues. The latency issues might be due to outstanding I/Os, network hardware issues, network congestions, or disk slowness.

The trip analyzer allows you to get the breakdown of the latencies at each layer of the vSAN stack. The topology diagram shows only the hosts with VM I/O traffic.

Note: All the ESXi hosts and vCenter Server in the vSAN cluster must be running 7.0 Update 3 or later.


Turn on the vSAN performance service before you can run the test and view the latency issues.


  1. Navigate to the vSAN cluster, and select a VM.
  2. Click the Monitor tab.
  3. Under vSAN, select I/O Trip Analyzer.
  4. Click RUN NEW TEST.
  5. In the Run VM I/O Trip Analyzer Test, select the duration of the test.
  6. Click RUN. The trip analyzer test data is persisted and is available only for 30 days.
    Note: vSAN does not support trip analyzer in the stretched cluster, two-node cluster, and virtual disks in remote vSAN datastore.
  7. Click VIEW RESULT to view the visualized I/O topology.
  8. From the Virtual Disks drop-down, select the disk for which you want to view the I/O topology. You can also view the performance details of the network and the disk groups. Click the edge points of the topology to view the latency details.