It is commonly recommended that one shouldn't fill a ZFS volume beyond 70-80% to prevent fragmentation. I, however, find that I have gone beyond that in the past (the "I need just a bit more, I'll clear it later"-syndrome). I'll soon migrate some of my volumes to new ones so they are 'clean' again, and would like to enforce a limit on said volumes. Essentially an all-user quota to prevent me from ever crossing that barrier.
So, is it as simple as just setting the following (assuming a 3TB disk in this case)?
zfs set quota=2000G storage/data
If so, is it possible to use a percentage here instead?
Finally, given larger volumes, is the recommendation still 70-80%, or should one calculate a more reasonable amount by multiplying the largest possible file to be stored/copied on it times an x amount (much like one would not set monitoring to throw a critical alert on 90% of a 10EB volume but would calculate average data-growth and set something more realistic instead)?
I guess I can discover the first to questions with some googling, but the final question is aimed towards the experts.