graid3 - requirements or manpage wrong?

[Eirik Øverby]

Hi,

to the best of my ability I have been investigating the 'real' 
requirements of a raid-3 array, and cannot see that the following text 
from graid3(8) cannot possibly be correct - and if it is, then the 
implementation must be wrong or incomplete (emphasis added):

label      Create a RAID3 device.  The last given component will contain
                parity data, all the rest - regular data.  ***Number of 
compo-
                nents has to be equal to 3, 5, 9, 17, etc. (2^n + 1).***

I might be wrong, but I cannot see how a raid-3 array should require 
(2^n + 1) drives - I am fairly certain I have seen raid-3 arrays 
consisting of four drives, for example. This is also what I had hoped to 
accomplish.

Anyone care to shed a light on this? I'd prefer to use graid3 (or 5, if 
there was one) instead of gvinum..

Thanks,
/Eirik