vSAN Health Service - Network Configuration - vMotion: Basic Connectivity Check

Products

• VMware vSAN

Issue/Introduction

Because vMotion is not able to check the configuration of the physical network, one way to ensure that IP connectivity for vMotion exists among all ESXi hosts in the vSAN cluster is to ping each ESXi host on the vMotion network from each ESXi host.

The Basic Connectivity check for vMotion, also known as a unicast or small ping test, automates the pinging of each ESXi host from each of the other ESXi hosts in the vSAN cluster and ensures that connectivity between all the ESXi hosts on the vMotion network exists. In this test, all nodes ping all other nodes in the cluster.

Environment

VMware vSAN (All Versions)

Resolution

The basic ping test is performed using very small packets, so it ensures basic connectivity.

If the test fails, it indicates that the network is misconfigured. The test sends three pings. It shows a warning when one ping is lost and an error when two or more pings fail.

The failure could be caused by many factors. They might include problems in the virtual network, including VMkernel adapters or Virtual Switches. Or problems in the physical network, such as cables, physical NICs, or physical switches.

Examine the other network health check results to determine the cause of the misconfiguration. If all other health checks indicate a good configuration on the ESXi side, most likely the issue resides in the physical network.

To manually test the vMotion network run the following command vmkping -I vmk(x) (where x is the number of the vmkernal adaptor for the vMotion network) -s 1472 <vMotion IP of a neighboring host>

Example: vmkping -I vmk1 -s 1472 192.168.x.x
Note: you can also add the -d switch for do not fragment but it's best to test without this switch first to ensure basic ping works

See KB Testing VMkernel network connectivity with the vmkping command for more details about using vmkping.

For more information on collecting VMware vSAN logs, see Collecting vSAN support logs and uploading to VMware.

Also, see:

• VMware vSAN documentation on the VMware Virtual SAN Documentation site
• VMware vSAN Diagnostics and Troubleshooting Reference Manual
• VMware vSAN Design and Sizing Guide
• VMware Ruby vSphere Console Command Reference for vSAN (Attached to this KB)