[lscotte]

The keyword is definitely "ideally" :-) With a cloud provider like AWS, storage is always virtualized - so we've always got that working against us. I see ZFS in AWS more about flexibility than data integrity, although having said that ZFS should do just as well or better (certainly no worse) than EXT4, XFS, or BTRFS for reliability. The ability to add storage dynamically without having to move bits around is powerful.

[drvdevd]

And I've actually had (a couple times now) random hardware failings, with random notification emails from Amazon, on EBS storage on AWS, with accompanying data loss.

Might as well treat your zpool like it's on real hardware and configure raidz accordingly. The cloud does have real, problematic hardware behind it, and it's important to remember that.

[edit] especially if you can configure your block devices such that you know they're sitting on different physical hardware at the cloud data center, you will gain that benefit of ZFS