Today when I booted my lab I saw some issues with one of the host and the summary page of host was showing the below error

“The vNetwork Distributed Switch configuration on some hosts differed from that of the vCenter Server.”

The cause of this issue can be explained as follows:

When we install distributed switch and add hosts to the vDS a hidden switch is created on all hosts and a copy of  vDS database is copied to each host with information on the switch. This database is synched every 5 minutes.

vDS are created and managed from vCenter as it holds the management plane and the the part of vDS which get installed on per host level is called IO plane. So if ever vCenter Server is down it will not affect the VM traffic on the host and you will only loose management capabilities.

Selecting the vDS and navigating to host tab will show you a warning (under VDS status) that your host is out of sync. No need to panic here.

By default the vDS database is synched on all hosts every 5 minutes. If it is not happening you can trigger a force resync.

Go to Networking view in vCenter, Select the vDS and select the host which is out of sync. Right click on host and select option “Rectify vSphere Distributed Switch on Host” option.

Again it will not show you the desired result immediately and you have to wait for 5 minutes.

In my lab it took some good 10 minutes for out of sync warning to disappear.

I hope this post is informational to you. Share this post on social media. Be sociable 🙂