I found some unexpected behavior when updating my cache drive from 2x1TB btrfs RAID1 to a single 2TB zfs volume. The "Only move at this threshold of used cache space" setting is compared in the mvallfrompool() function with (zpool get -o value capacity). The output from zpool is at a granularity of 1 percent. This means that unless the cache utilization is more than 1% (which can be pretty large on bigger cache volumes), the mover won't do anything. Is it possible to change this to a value with higher granularity (perhaps df in bytes or similar)?