At the time of initial cluster build, you can choose the MTU size to assign to the virtual-distributed switches. This allows you to configure the switch ports supporting the VxRail cluster to match the MTU setting on the virtual-distributed switches and reduce the potential for network fragmentation.
You can choose to run the VxRail cluster at the default MTU size of 1500, or instead choose a larger MTU if your network supports it. If your data center network supports jumbo frames, Dell Technologies recommends configuring the MTU size at 9000. A resource-intense network such as vSAN is better suited for a network configured with jumbo frames.