VSAN-Troubleshooting-Reference-Manual

Diagnostics and Troubleshooting Reference Manual – Virtual SAN
Once the full charts view is expanded, what is notable is that the amount of data
transmitted and received on the Virtual SAN network is rather small:
This is taken from the host where the virtual machine resides. These hosts use 1Gb
NICs, which are fully supported by Virtual SAN, but should be dedicated to Virtual
SAN traffic. So why is the TxMBps and RxMBps so low when we are clearly wishing
to drive far more IOPS than we are achieving?
In this scenario, using the Network I/O Control feature of a distributed switch to
limit the Virtual SAN network traffic produced this situation. Although somewhat
contrived, it is an accurate reflection of the behavior that may be observed in Virtual
SAN if the network is suffering from issues. In fact, we had a customer situation
where the switch was sending excessive pause frames (in the millions) impacting
Virtual SAN traffic and leading to extremely poor latency for the virtual machine
workloads (observed via the client and DOM owner views) but no latency issues on
the disks view.
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