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 EMC recommends configuring the MTU size at 9000. A resource-intense network such as vSAN is better suited for a network configured with jumbo frames.