I’m stuck on the choice of OS. Ubuntu supports ZFS natively now, and that’s appealing, but so is a more proven solution such as FreeNAS 8 or NAS4Free. I do also partly question “do I really want ZFS?” – the reason perhaps for not doing it is that the disks may well be quite mixed in size. I can’t really imagine a decent ZFS config where you have 2x 500GB disks, 2x 1TB, 2x 1.5TB and a 3TB drive, for example. You’re going to end up wasting a lot of space, somewhere.

I contemplated the idea of creating RAID-Zs from vdevs made of 500GB partitions, spread across the disks and then shoving them all into one Zpool but this seems messy and it’s suggested the performance takes a hit. This might not play with will FreeNAS/NAS4Free either, and perhaps I’d be better off using OpenIndiana/Nexenta.

Any advice for what to do, given the changed availability of software 2 years after this article was written?

It’s better to move Transmission’s configuration directory to somewhere on your ZFS pool. By default, I think it is stored in memory (assuming you are booting from a USB flash drive), so it’s lost whenever you reboot.

Thanks!