Hi nosan,

it's a good idea that you want to add redundancy to your SAN. Once you have the second switch install you do NOT want to ISL both switches together as that will create one big fabric. With one big fabric any disruption in the fabric may cause issue for all systems. By keeping switches separate, you create two separate fabrics. If you need to perform some kind of maintenance on one switch ..your hosts still have one available path to storage. Next thing would be to connect SPs correctly where switch 1 is connected to SPA0 and SPB0 and on switch 2 you connect SPA1 and SPB1. I am assuming that you are running license PowerPath. So now when you zone your systems you can zone one HBA to SPA0, SPB0 and zone second HBA to SPA1, SPB1. Not only will it give you increased redundancy but it will also give your load balancing where if LUN is owned by storage processor A ..your server will be able to send/receive data to it using both HBAs since both HBAs have access to SPA.

related discussion

http://forums.emc.com/forums/thread.jspa?threadID=89431&tstart=0

There's nothing more to say. Dynamox's answer covers it all

Dynamox,

Thanks for a clear and descriptive answer. Now, I understand how it should be hookup. I do have an licensed Powerpath s/w.

Thanks again,

nosan