Here’s a quick topic that I don’t see covered very often: the vSphere Distributed Switch Health Check.

What is it, and what does it offer? Let’s take this definition from the official VMware vSphere documentation and the VMware by Broadcom Knowledge Base (KB).

The health check support helps you identify and troubleshoot configuration errors in a vSphere Distributed Switch. Use vSphere Distributed Switch health check to examine certain settings on the distributed and physical switches to identify common errors in your environment’s networking configuration. The default interval between two health checks is 1 minute.

Ok, makes sense – so let’s take a closer look on how to enable this and use it to troubleshoot a vSphere distributed switch (vDS).

We’ll make sure to turn it off afterward because this health check feature generates a lot of MAC table entries and increases network traffic when it is enabled.

To enable the Health Check, log in to vCenter, navigate to the Networking panel, and click on a vDS. Then go to the Configure tab and click on Health Check.

Over on the right side of the panel there will be an Edit button. Click that and the Edit Health check Settings panel will pop up.

Each state – vLAN and MTU and Teaming and Failover are currently disabled as mentioned earlier by default.

vLAN and MTU refers to and reports the status of distributed uplink ports and VLAN ranges.

Teaming and Failover checks for any configuration mismatch between the ESXi host and the physical switch used in the teaming policy.

I’ll go ahead and enable this for both states. By default the health check interval is 1 minute – if wanted, the interval can be increased.

With the health check enabled, then we’ll go to Monitor and click on Health. Now there is a health chart/matrix here where if there are any issues with vDS status or health it will report here. Everything looks fine here…

Now, if there were an issue, there will be a notification here.

Something like the below would show…as this illustrates an issue with VDS sync between hosts and an issue with NIC teaming and failover – from here I would begin to troubleshoot and resolve the issues until the board goes green again.

Additional details can also been seen in the lower panel.

Hopefully, this tip and trick will be useful to anyone reading this. If it helped you, leave a comment below and let me know! Don’t forget to subscribe to the blog and check out the other posted content. Thanks!