I have an HP Smart Array P400i raid controller, with 6 disks, working in a RAID 1+0. This is what it looks like:

     Mirror Group 0:
        physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 72 GB, OK)
        physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 72 GB, OK)
        physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SAS, 72 GB, OK)
     Mirror Group 1:
        physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SAS, 72 GB, OK)
        physicaldrive 2I:1:5 (port 2I:box 1:bay 5, SAS, 72 GB, OK)
        physicaldrive 2I:1:6 (port 2I:box 1:bay 6, SAS, 72 GB, OK)


If my understanding is correct, drives 1 and 2 could fail, and the RAID would still be ok.

This doesn't seem right to me, I was thinking a RAID 1+0, with 6 drives should look like this:

     Mirror Group 0:
        physicaldrive 1I:1:1 (port 1I:box 1:bay 1, SAS, 72 GB, OK)
        physicaldrive 1I:1:2 (port 1I:box 1:bay 2, SAS, 72 GB, OK)
     Mirror Group 1:
        physicaldrive 1I:1:3 (port 1I:box 1:bay 3, SAS, 72 GB, OK)
        physicaldrive 1I:1:4 (port 1I:box 1:bay 4, SAS, 72 GB, OK)
     Mirror Group 2:
        physicaldrive 2I:1:5 (port 2I:box 1:bay 5, SAS, 72 GB, OK)
        physicaldrive 2I:1:6 (port 2I:box 1:bay 6, SAS, 72 GB, OK)


The data would be striped across the 3 mirrored pairs. 

Are both configurations possible, or just the first?


Question: can I use a disk larger than 320 GB with RPi?
Answer: I have a 500Gb HDD formatted with ext3. I've connected it to my RPi using a USB->SATA enclosure and everything works just fine. Using ArchLinuxARM though. So I don't think there are any limitations on disk size for RPi.