ZFS bug in FreeBSD and FreeNAS
After a few weeks using FreeNAS 8.3.1, I noticed I could not create new volumes because the pool was out of space. The problem was that I should have had enough space, by a long shot. In fact, one of my “block” volumes was taking space more than twice it’s size. I had other volumes that seemed unaffected (or less affected), the only difference was that the problematic volume had volblocksize=8k set ....