Dell MD3200i and EqualLogic - iSCSI network config recommendations

Hi

I have an existing VMWare vSphere 4.1 infrastructure with 3 hosts and an EqualLogic iSCSI SAN. Each host has 8 pnics of which 2 are dedicated to iSCSI. iSCSI traffic also runs on dedicated switches.

We now have a spare Dell MD3200i SAN available which I would like to integrate into the existing storage network. I thought this would be a fairly painless process of just configuring all the ports on the MD for the existing iSCSI subnet, create some new VMkernel ports on each host and bind pnics to the relevant vmk ports. After much investigation this doesn’t appear to be the optimum config.

Dell state in their MD3200i deployment guide for vSphere 4.1 that:

“It is recommended that you have different ports on different subnets due to throughput and pathing considerations….

Multiple subnets should be allocated by the number of array ports per controller. With the MD3200i you only get an active path to multiple ports on the same controller if they are on different subnets. Likewise, with VLANs, for multiple target ports on the same controller you only get an active path if the target ports are on different VLANs. Since the MD3220i has 4 ports per controller you get your best throughput with 4 subnets.”

Conversely the recommended config for the EqualLogic is all ports on the same subnet (which I believe is also generally the VMWare stance)

I seem to have a number of options:

1. Continue as planned and place all ports on the same subnet (probably not a realistic option as according to the above, I will only have 1 active path at a time)
2. Create new subnets for the MD. Create new VMkernel ports on the new subnets. Bind pnics to the vmks. Separate the traffic using VLANs.
3. Free up another 2 pnics on each host and use these for the MD iSCSI networks, thus separating the 2 SANs

Further to option 2, is there any issues separating iSCSI traffic using VLANs as I have never even considered this before?

Does anyone have any experience of running an MD3200i or similar in a mixed SAN environment?

Thanks in advance for any advice.

Cheers

Nick