I've successfully followed your recommendations (8.3 -> create raidz3 pool -> upgrade to 9.1.1) and everything seems to be working well. Took me a bit of time to set permissions up, they are not very intuitive, but fortunately the forums here are great and I did some reading and eventually figured it out. So anyway, I've noticed that the available size on my pool is 4.1TB - somewhat less than i would have thought: 2x2TB, 2x1.5TB, 3x1TB in raidz2, so that's 5 drives contributing 1TB each and 2 parity drives. I know one only gets about 930GB of usable space from a 1TB drive, so that would total around 4.65TB. The swap partitions would cost 10GB, bringing it down to 4.64. That means i'm short by about 500GB - is that how much I lose from having a non-optimal 7 disk raidz2 pool, or are there other factors?