@jgallagher noted this in https://www.illumos.org/issues/15432. Duplicating content here so we don't lose track of it:
https://illumos.org/books/zfs-admin/gavwn.html has a couple links to a "ZFS best practices guide" at http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide, but it appears solarisinternals.com is dead and possibly hijacked. Clicking on it I get taken through what looks like adware routing; I landed on wikipedia a couple times and Home Depot once (??).