An order of magnitude higher IOPS needed with ZFS than UFS

[Mark Felder]

On Tue, 11 Jun 2013 16:01:23 -0500, Attila Nagy <bra at fsn.hu> wrote:

> BTW, the file systems are 77-78% full according to df (so ZFS holds  
> more, because UFS is -m 8).

ZFS write performance can begin to drop pretty badly when you get around  
80% full. I've not seen any benchmarks showing an improvement with a very  
fast and large ZIL or tons of memory, but I'd expect that would help  
significantly. Just note that you're right at the edge where performance  
gets impacted.