Confirmation before buying hardware

[Bidule0hm]

Hi,

I will buy the components tomorrow so I would like confirmation that all is good (especially for the network controller), thanks :)

MB -> Asus Z87-Pro

CPU -> Intel i5 4430 - 3GHz

RAM -> (2x) Corsair XMS3 DDR3-1333 8Go CL9 (CMX8GX3M1A1333C9)

HDD -> (4x in a RAID-Z2) Seagate 3To S-ATA III 64Mo (NAS HDD) (ST3000VN000)

PSU -> Seasonic 560W X-Series

And I've a question: I've read it's not possible to expand a vdev but I also read that selecting more disks to create the vdev (and thus leaving some not physically connected) I could extend it in the future so what is the real answer ? I've also read that the only way to expand is to create dummy files to simulate the disks that aren't there yet, it's possible ?

My plan is to add 2 more disks and again 2 more disks in the future to expand the raid to 6 then 8 disks. But if I can't I would have to create another vdev of 4 disks and thus lose 2 disks storage size for another useless parity (--> (2 + 2) + (2 + 2) while I would have (2 + 6) = vdev).