In this setup it's not required as traffic is physically isolated and switches are dedicated for iSCSI traffic.

The reason to use 2 switches is in case you have a problem on the subnet (rare broadcast storm for example), but also in case the switch fails.

Using 2 VLANs on the same switch would protect against one of these, but not the switch failure.

I'd suggest 2 VLANs where each VLAN is on a different switch (or if you're using a core-switch, put each VLAN on a different blade in the switch so you can replace a whole blade without losing complete SAN connectivity).

"The reason to use 2 switches is in case you have a problem on the subnet (rare broadcast storm for example), but also in case the switch fails.

Using 2 VLANs on the same switch would protect against one of these, but not the switch failure.

I'd suggest 2 VLANs where each VLAN is on a different switch (or if you're using a core-switch, put each VLAN on a different blade in the switch so you can replace a whole blade without losing complete SAN connectivity)."

As a continuation of the thread,

We have an identical configuration as described in this article. However, we have two MD3000i's, both configured in the same way as the article, utilising the same two switches. These switches have been dedicated for iSCSI traffic.

Initially I had both MD3000i's setup on the same iSCSI subnets utilising different IP addresses. Dell support has suggested best practice is to separate the iSCSI traffic of both MD3000i's on their own VLAN's and subnets if utilising the same switches. i.e, There would be a total of 4 iSCSI VLANs, two on each switch, instead of the 2 native iSCSI VLAN's currently being used. Firstly, I want to double check that this is indeed a best practise.

Secondly, as the switch ports (we will be using Cisco 2960's) will be configured for access ports and not trunkports, is there any need to specify the VLAN in the VNic Config? That is, the VMKernel configuration has a field to specify the VLAN, presumably for cases where iSCSI traffic will be used across trunking ports so it can tag the traffic. Since we're not using any form of trunking, would it be safe to exclude the VLAN ID from the VMKernel configuration?

Thanks in advance.

Gene