It is just a subnet for storage and backup.
There is a Service Console on both VSwitch0 (100BT) and vSwitch1 (GB).

Changing the DNS entry is not necessarily what I want to do,
management access trough 100BT but backup/storage through GB.

I will do a test vcb backup with -h to the ESX (GB) first.

root@vclnode03 root# esxcfg-vswitch -l
Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch0 64 4 64 1500 vmnic0

PortGroup Name VLAN ID Used Ports Uplinks
VM Network 0 0 vmnic0
Service Console 0 1 vmnic0

Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch1 64 8 64 1500 vmnic5,vmnic4

PortGroup Name VLAN ID Used Ports Uplinks
SAN Network 0 2 vmnic4,vmnic5
Servicekonsole ISCSI0 1 vmnic4,vmnic5
VMkernel ISCSI 0 1 vmnic4,vmnic5

Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch2 64 5 64 1500 vmnic7

PortGroup Name VLAN ID Used Ports Uplinks
Servicekonsole 0 1 vmnic7
VMkernel VMotion 0 1 vmnic7

Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch3 64 9 64 1500 vmnic2,vmnic1

PortGroup Name VLAN ID Used Ports Uplinks
Virtual Machine Network 1130 5 vmnic1,vmnic2

Switch Name Num Ports Used Ports Configured Ports MTU Uplinks
vSwitch4 64 1 64 1500

PortGroup Name VLAN ID Used Ports Uplinks
Temp VSwitch 0 0

root@vclnode03 root#