How to connect a disk shelf without a switch to two servers?

Question

NAS

There is a shelf of IBM DS3512 disks (with two two-headed controllers) and two HBA Qlogic (also two-headed) for inhuman experiments. There is no FC switch. I want to:

1. Connecting a shelf to one server is just like a disk
   
2. Make an array bootable
   
3. Connect the shelf to two servers with a manual failover (the server died - we load the second one from the same "disk")
   

I connected it simply: from each server, one patch cord to each controller. I created a group of hosts on the shelf, so far included one of the four hostports in it, created two fifth raids from the disks and tied them there.
From the server I saw sda and sdb of the appropriate sizes, they can be split with cfdisk, but neither pvcreate nor mkfs want to work further - they swear, they say, the disk is connected somewhere else.
Am I going in the right direction at all? Should I twist the arms of multipath or pull out patch cords? Everything found on the net "for dummies" starts with switches and zoning, but I don't have a switch.

Answer 1

Twist the arms of multipath, as most likely the system itself does not recognize the connection as a single disk. We have a similar configuration with ds3400, it works without a switch directly to two servers...