What are my controller options for 24 SATA disk S/W RAID?
 

An X-Case RM 424 case can accommodate 24 drives. The drive section presents six SFF-8087 (SAS) sockets on the backplane, each of the 6 connecting 4 drive bays.

If I understand correctly, I have a choice between using either a SAS or a SATA Controller. I plan to use software RAID (CentOS 6.x). so don't need RAID on the card. JBOD is fine. The disks will be SATA.

If I use a SATA controller (or 2, as required) with port-multiplier capability, can I concentrate connections from the port multipliers to the backplane using six 4xSATA-->SFF-8087 cables? Or since this would make it look like I dropped spaghetti bolognese in my case, is there a neater alternative along the lines of a SATA port multiplier with a SFF-8087 (diskward) connector?

What options exist for using a SAS HBA & SAS expander? Whilst this might be tidier, is it a lot more expensive than using SATA+PMs?

Suggestions and recommendations for specific hardware are welcome, as would be links to accounts of similar projects!

I'd be more tempted to go with real hardware raid if you are spending this much money.

+1 ^^^ definitely I'd go with it too.

jefro & lithos, Thanks for the input. I haven't ruled out hardware RAID as an option, just leaning towards software for now. So happy to hear all suggestions for component sets & cabling between the PCI express slot and the backplane.

Not sure what to say. I'd look at some of the storage arrays offered by big server companies. They make this all plug and play. By the time you fooled with all the setup and connections and what not you could have one of their managed arrays.