Raid 1 on Z420 and drives size

Hi to all,

In these day I was planning to do a little backup system using an "old" z400......but i've found on his quickspecs pdf that it can't do Raid 1 array bigger than 2TB "All RAID arrays must be less than 2 TB, except for SATA RAID 0 Data Arrays.".

So, Now, I/m looking to do the same but on a Z420, Which his quickspecs pdf tells that "RAID arrays greater than 2 TB are fully supported."

So....Mine questions are (before to proceed to purchase one Z420)

A) ALL the version/edition of Z420 have a integrated Raid controller?

B) Can i do a boot with a normal drive (A small drive, like a 250gb ssd or 500/1000tb normal drive) and create a Raid 1 Array with a couple of 6 or even 8TB drives with the integrated controller?

C) How much is the maximum drive size allowed (Speaking of a SATA drive)?

Thanks for any answer

Sorry to all about my poor english :)

Have a great day