VSAN-Troubleshooting-Reference-Manual

Diagnostics and Troubleshooting Reference Manual – Virtual SAN
II – Using VSAN Observer to troubleshoot a network
performance issue
As Virtual SAN is a scale-out storage solution, performance of the network
interconnects is also a key factor in validating performance. There have been a
number of situations where customers have observed high latency during a test run.
The next step is obviously to identify and then isolate the source of the latency.
An easy way to figure out whether the source of latency in a performance test run is
potentially the network is to compare latency figures seen at the VSAN Client tab
and the VSAN disk tab. If the latency at the client tab is much higher than what is
seen at the disk tab, the network could potentially be a source of latency, and you
should validate that your network configuration is appropriate.
In this example, there is a virtual machine running a particular workload. In this
case, it is IOmeter, running a 70% read workload, 70% random. The Outstanding IO
value is set to 8, and there is only one worker thread. The
NumberOfFailuresToTolerate has been set to 1. The virtual machine is producing a
nice steady 2,000 IOPS giving us a throughput value of 8MB per second.
The host is deployed on host cs-ie-h04. The VMDK object that is the destination of
the IOmeter workload is mirrored across host’s cs-ie-h01 and cs-ie-h04.
Let’s begin by taking a look at performance in steady state.
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