VMware vSAN Performance Degradation Due to Physical NIC Errors

Products

• VMware vSAN

Issue/Introduction

Symptoms:

• Performance degradation may appear  for virtual machines. .
• Inter-host packet loss observed during network testing.
• Elevated vSAN read and write latency (hundreds of milliseconds) appears at the virtual machine client level .

       

•  vSAN backend disk latency appears normal.

       

Environment

VMware vSAN 8.x

Cause

• Physical network interface errors appears on multiple hosts affecting vSAN traffic carried over vmnic.
• Packet loss confirmed through ping tests.

root@esx :~ ] vmkping -I vmk3 10.1##.1##.2# -d -s 8972 -c 20

10.1##.1##.2# ping statistics
packets transmitted, 18 packets received, 10% packet loss
Round-trip min/avg/max = 0.177/0.214/0.273 ms

Resolution

Engage the physical network team to investigate and address network related issues.