C'est BSD là pas linux
Sinon : http://www.freenas.org/whats-new/2015/02/a-complete-guide-to-freenas-hardware-design-part-i-purpose-and-best-practices.html

ZFS wants direct control of the underlying storage that it is putting your data on. Nothing will make ZFS more unstable than something manipulating bits underneath ZFS. Therefore, connecting your drives to an HBA or directly to the ports on the motherboard is preferable to using a RAID controller; fortunately, HBAs are cheaper than RAID controllers to boot! If you must use a RAID controller, disable all write caching on it and disable all consistency checks. If the RAID controller has a passthrough or JBOD mode, use it. RAID controllers will complicate disk replacement and improperly configuring them can jeopardize the integrity of your volume (Using the write cache on a RAID controller is an almost sure-fire way to cause data loss with ZFS, to the tune of losing the entire pool).