VMware vSphere 6.7 comes with a new version of DVS, 6.6. VMware recommends the following:

• Perform the upgrade to DVS 6.6 during a maintenance window.
• NOTE: Upgrading a DVS affects all hosts on the DVS at once. To avoid possible issues to all hosts, make a new DVS at the appropriate version level, then move hosts and objects from your current DVS over to the new DVS after creation.
• Change the DRS mode to manual before initiating the upgrade and skipping DRS recommendation for the duration of the upgrade. You can reset the DRS mode to its previous state once the DVS upgrade is complete.

Important: Upgrading to DVS version 6.6 is not supported with NSX for vSphere while running vCenter Server 6.7 and should not be attempted until you completed your upgrade to vCenter 6.7 Update 1.

VMware vCenter Server Appliance 6.5.x
VMware vCenter Server Appliance 6.7.x
VMware vCenter Server 6.7.x
VMware vCenter Server 6.5.x

Note: NSX customers should upgrade to vCenter Server 6.7 Update 1 prior to upgrading vSphere Distributed Switches. VMware does not recommend to run a VM migration using vMotion or change the DRS to manual during the DVS upgrade to 6.6.

DVS upgrade to version 6.6 might fail if there are vMotion tasks running in parallel or Attempting multiple DVS upgrades to version 6.6 may cause some of them to fail

Symptoms:

• The DVS 6.6 upgrade operations fails.
• VDS status in the UI displays the message similar to:
  
  Out of sync
   
• You see a message in the UI as well as in the vpxd logs similar to:
  
  Cannot complete a vSphere Distributed Switch operation for one or more host members.
   
• Also, the DVS summary contains the message similar to:
  
  The vSphere Distributed Switch configuration on some hosts differed from that of the vCenter Server.

Important:

• If a vMotion operations are happening in parallel, the dvports of the DVS are subject to change (may be added / removed). This could lead to a an issue with the dvport configuration during the DVS upgrade.
• If multiple DVS’es are being upgraded subsequently (with some of the DVS upgrades pending), some of the DVS Upgrades may fail with timeout. This occurs since the upgrade of these DVS’es may take some time to complete due to having a large number of ports allocated on them.

To resolve this issue:

1. Click on the DVS summary in the vCenter Server UI.
2. You should see this message:
   
   The vSphere Distributed Switch configuration on some hosts differed from that of the vCenter Server.
    
3. Click the Rectify option displayed as part of the message. Alternatively, wait for the vCenter Server to rectify the DVS. This is done periodically every couple of minutes.
   
   
   
   Note: If the DVS fails to auto sync with the Rectify button, see "The vSphere Distributed Switch configuration on some hosts differed from that of VMware vCenter (2042692).

vMotion operation fails with timeout if a vMotion task is happening during DVS 6.6 Upgrade

To resolve this issue, retry the vMotion operations once the DVS upgrade completes.

VMs and vmknics lose network connectivity if LAG ports are connected to DVS after VMs are connected and the DVS is upgraded

To resolve this issue, trigger reconfiguration of the affected VM by changing any DVPortgroup setting in the vCenter Server UI or through the API.

DVS upgrade to version 6.6 fails if the VMs vNIC portgroup is configured with PVLAN feature

To resolve this issue, migrate the virtual machines using vMotion out of the host, or power off the virtual machines. DVS upgrade should naturally proceed after 30 minutes.