ZFS ARC Shrink / flush cache without exporting
# https://openzfs.github.io/openzfs-docs/man/master/4/zfs.4.html#zfs_arc_shrinker_limit
echo 0 | sudo tee /sys/module/zfs/parameters/zfs_arc_shrinker_limit
echo 3 | sudo tee /proc/sys/vm/drop_caches
echo 10000 | sudo tee /sys/module/zfs/parameters/zfs_arc_shrinker_limit