Remove physical Controller from IBM DS3500 SAN

Log onto IBM System Storage DS Storage Manager for your DS3500

Enter into you SAN

Go To Advanced->Troubleshooting->Prepare for Removal

Choose your Enclosure and the Controller.

There will be a Green light on an OK when the SAN is ready for you to remove the Interface.

Only remove one interface at a time.  Make sure the first Interface is back online before you take the second interface down.