My assumption here is that this device is no longer under support but if it is, I would highly recommend getting c-mode licensing and upgrading it to 9.1, the latest that is supported. Once you're on 8.3+, you can do Advanced Disk Partitioning and recoup a lot of space lost to root aggregates.
However, since my assumption is that it is no longer under support, then we have to work with what you've mentioned. Since you're on 7-mode, there's no requirement for a dedicated root aggregate so you're going to lose 2 disks to RAID for either controller. If you're trying to squeeze as much space out of it as possible and you can forgo high-availability, I would consider removing the second controller and devoting all 12 disks to the now, single-controller. That way you would lose 2 disks to RAID and keep one spare, giving you just under 4TB of usable storage. Otherwise, if you want to keep HA, I would do 6 drives per controller, losing 2 to RAID and 1 spare each. You'll end up with about 1.3TB of usable storage per controller. You could also consider running RAID-4 and you'd end up with about 1.8TB of usable storage per controller.
Since you're using iSCSI, best practice is to not use LACP. Assign IPs to all four 10Gig ports and let MPIO sort out pathing.
I'm not sure what you mean about e0M being partners in the same subnet. If you're saying they're in the same subnet, that's fine, your out of band module will also be in that subnet, I can't remember if it was an SP or BMC on that model, but the wrench port has two interfaces behind it, e0M and your out of band.
You may want to spend some time reading the documentation located here.
and thanks for yor Help.
