What are the cheapest drives we can use for ZFS NAS for occasional media access?<p>Can we use the absolute cheapest Western Digital Green drives, with limited lifespans?  Does ZFS spin down drives when not in use?<p>Actually, how long do the cheapest drives last when spinning 24x7?<p>I ask because Best Buy has 5TB Western Digital drives for $110 today:  <a href="http:&#x2F;&#x2F;www.bestbuy.com&#x2F;site&#x2F;wd-my-book-5tb-external-usb-3-0-hard-drive-black&#x2F;4222407.p" rel="nofollow">http:&#x2F;&#x2F;www.bestbuy.com&#x2F;site&#x2F;wd-my-book-5tb-external-usb-3-0-...</a><p>But these consumer drives never list reliability figures, unlike data center drives.