omconfig and createvdisk: unexpected result?

Hi All,

I'm having an issue with setting up a "Dell HPC NFS Storage Solution" 
system (an R710 and 2 MD1200s with 12 2TB disks each). I'm following the 
guidelines in the "Dell HPC NFS Storage Solution" (Sept. 2010) document
I was sent by a Dell representative (although it can also be found online, 
and seems to be the latest).

I'm following the procedure in "Appendix B: Integrating Dell NSS into a 
High Performance Cluster", but I'm using Ubuntu Server 12.04.

When I get to "configuring the LUNs on the MD1200" (page 33) and create a 
vdisk using omconfig I try the command in the document. Here's the command 
in all its glory:

/opt/dell/srvadmin/bin/omconfig storage controller action=createvdisk 
controller=1 raid=r60 size=max stripesize=512kb
pdisk=0:1:0,0:1:1,0:1:2,0:1:3,0:1:4,0:1:5,0:1:6,0:1:7,0:1:8,0:1:9,0:1:10,0:1:11,1:0:0,1:0:1,1:0:2,1:0:3,1:0:4,1:0:5,1:0:6,1:0:7,1:0:8,1:0:9,1:0:10,1:0:11
spanlength=12

(On running it I get the "Command successful" response and no other 
messages.)

That is putting all 24 2TB drives in one virtual disk. So I expect to get 
about 36TB of space. I actually get a vdisk of 22TB. If I report on the
physical disks I see this for every physical drive.

Capacity                  : 1,862.50 GB (1999844147200 bytes)
Used RAID Disk Space      : 1,117.50 GB (1199906488320 bytes)
Available RAID Disk Space : 745.00 GB (799937658880 bytes)