I've got an LSI2208 integrated raid controller on a Supermicro X9DRH server board. It currently has a Logical Drive (LD) composed of 4 spinning disks. Now I want to add some more drives in JBOD, to let the OS access them directly (as opposed to creating a dedicated RAID0 LD per disk).
There are a couple of links (here for instance) explaining how to enable JBOD mode on LSI2208 controllers. This seems to be an all-or-nothing switch: either JBOD is supported on the controller, or not.
The command:
megacli -AdpSetProp EnableJBOD 1 -a0
... would enable JBOD mode on controller 0
From reading here, it seems that disks plugged into the controller but not associated with a Logical Disk become visible to the OS.
The question: is this a destructive operation? What happens to existing (RAID5/1/0) Logical Disk once this is done ? Or does this only affect disks not yet allocated to a Logical Disk ?
I could just try it out, but that means backing up several TB of data first.
Hope someone has an answer!