XigmaNAS

My server can hold 17 drives.

Any foreseeable issues with 17 drives in RaidZ3?

I assume you mean in one pool

Have a look at this http://blog.delphix.com/matt/2014/06/06 ... ipe-width/

I have been looking for something just like this!

Thanks for the great help. 10/10

Do you think it's better to do two nine disk Vdevs?

I'd be looking at 6% disk space for parity at 32kb with 17 drives
I'd be looking at 13% disk space for parity at 16 or 32kb with two nine disk vdevs, but I'd have six disk failure capacity vs three.

also see
http://www.servethehome.com/raid-calcul ... tdl-model/

2 x vdevs should scrub/resilver much faster and read iops around twice as fast - at the cost of 7% of your space, and you also get that higher survivability you mentioned. Seems like good idea to me.