Bryan O'Connor | 19 February 2013
vSphere 5.1 has introduced a lot of really useful functionality with the vSphere Distributed switches, Network Health Check helps avoid network setting inconsistency, which in turn avoids errors caused by misconfiguration
I've been playing with the new features of the Distributed
Virtual Switches in vSphere 5.1 lately as part of my prep for the
vSphere 5.1 Optimise and Scale
One of the new features is a marvellous thing called Network Health Check.
The purpose of this feature is to detect certain issues and inconsistencies between the physical and virtual networks.
Certain key parameters such as MTU, NIC Teaming configuration and VLANs need to be configured consistently on the virtual and physical networks. If not we could then get some rather dramatic network connectivity issues.
What Network Health Check does is to search for these inconsistencies and report them to the administrator.
Network Health Check can detect and report the configuration differences between the port group and the switch port configuration by using layer two Ethernet packets. At one-minute intervals (by default), request and acknowledge packets are sent back and forth between the virtual interface and the switch. When packets are dropped, a configuration warning is displayed on the VMware vSphere® Web Client.
The requirements for Network Health Check include:
For VLAN and MTU checks, there must be at least two physical uplinks connected to the distributed virtual switch.
For the teaming policy check, there must be at least two active uplinks in the team and at least two ESXi hosts connected to the virtual distributed switch.
For a wonderful little demo visit the VMware Knowledge Base .