I have an linux server with an LSI MegaRaid 320-2X SCSI Controller. It works fine and I have a bunch of disks being used by the operating system so the card and driver works fine.

I have added some new disks, initialized them etc and the lsi management software can see the disks and regards them as online, but the operating system cannot see them

There is not much point in having a hot-swap controller if the operating system can't make use of of though.

Is there any way to force the operating system to see the new disks...?

Adding the disks to the controller is one thing; now they need to be part of an array/logical disk group, most likely.

Since the MegaRaid 320 is a hardware RAID controller, the OS only knows of virtual disks presented to it by the controller--not individual ones. Seeing the new disks as "online" in the LSI utility is a good start--but I think you will need to create a new logical disk for them to be members of before you will see a new disk available in the OS.

I did created arrays out of them, and the logical drives are online as well, but the linux operating system still cannot see the new disk devices when doing cat /proc/partitions or fdisk -l or similar.

I'd really like linux to pick up the new disks without needing a reboot...

You haven't rebooted the machine?

No idea, then. This looks terribly complicated, and may not necessarily help, but it's the closest thing I can find on close examination of SCSI disks:

http://www-941.ibm.com/collaboration...f+SCSI+devices

Good luck!