Unlike esxtop, which collects real-time data, the vscsiStats tool is used to gather the I/O statistics of a VM at a per-virtual-disk (VMDK) level. It can collect statistics such as the number of outstanding I/Os, size of the I/Os, and seek distance and latency.
You will need access to the ESXi CLI via the console or SSH. Also, make note of the World IDs corresponding to the VMs you would like to fetch the statistics for. The
esxcli vm process list command will list all the running VMs with their World IDs.
To fetch the I/O statistics corresponding to a VM, you will need to find the
worldGroupID corresponding to the VM. This is achieved by issuing the following command:
# vscsiStats ...