Two things.
- You don't need any additional cables to do this. Just connect the SAS SFF-8087 cables currently linked to the motherboard RAID controller to your add-in LSI-9211-8i card.
- The Smart Array P420i controller with current firmware has a JBOD mode that can be set with the
hpssacli
utility.
modify [hbamode=on|off|?] Turning on HBA Mode will expose
the physical drives to the operating system and Smart Array
configuration will not be allowed.
The target can be any valid controller which supports this feature.
modify [raidmode=on|off|?] Turning on Raid Mode will allow
Smart Array configuration on the specified controller.
It would be helpful to understand why you're looking to run JBOD mode on this particular server. Are you planning on using ZFS or something like Storage Spaces? Or is it something more involved like VMware vSAN? Otherwise, this is an odd request for this type of server.
Please add some context, because it will help us help you.
edit
That controller is capable of 64 logical drives. It sounds like you're running this controller with NO read/write cache module. That's important to have. See this HP advisory.