Proper way to remove MD3000i from the system

Hi,

We have an MD3000i with two MD1000 expansion units that we are trying to decommission. They are setup (iSCSI) on a PowerEdge 2950 running RHEL5.

What's the proper way to take them offline? Do I have to shut down the host or can I just shutdown MD3000i, then two MD1000 without taking down the host? What should I change on the host so that Iit wouldn't look for the MD3000i in the future?

Thank you.

Alex.