NIC1 and NIC3 have both a physical and virtual IP (for failover).
Open-E support have told me that DSS V6 only supports one ping node. (I've actually tried using more than one ping node by entering 2 IPs separated by a colon. All that happened was a dramatic slowdown in the speed of the primary node and a nice red "fail" label in iSCSI Failover.)
However, because we're using MPIO, our iSCSI traffic travels through 2 NICs and therefore 2 subnets. As a result, we surely need to have a ping node on both subnets. Otherwise, if we unplug one of the network ports on the primary, or if the switch dies, then there is a risk of a failover - something that's going to be more hassle than it's worth.
One way of getting around the problem would be to put the ping node on one of the subnets with bonded NICs. However, this isn't representative of whether the iSCSI subnets are up or not. For example, the iSCSI nodes will function fine if the management network was to go down.
What do people generally use as a ping node? What network do your ping nodes sit on? How people get around the problem that I've described above?