ZFS with four drives

[ddimick]

Mirrored sets or raidz2? I've done a bunch of reading here and the ZFS best practices page and it seems I could get slightly better read performance with mirrored sets, but in a two-drive failure scenario I have an increased chance of losing the pool. And, since raidz2 cannot be expanded by adding drives, I must increase the pool with minimum four-drive raidz2 sets to stay consistent with this strategy.

Anything else I should be considering?

[Onichan]

Well my first question is are you planning on only a single gig connection? If so then I think your LAN will be your bottleneck and not the drives. So then that would make the question are you able to add 4 more drives down the road? If not then that would seem the answer is doing mirror sets, but if you are able to then I would say go RAIDZ2.

[raulfg3]

You still can grow RaidZ2 add other 4 drives ( other vdev of 4 drives in RaidZ2).

my experinece: use mirrored pools, use less CPU and are less data stress to disk , so lose 2 disk escenarios is really "rare", and is more easy to grow / maintain.