Here are the details.
cnjr-opennms>root$ zfs list
NAME USED AVAIL REFER MOUNTPOINT
openpool 20.6G 46.3G 35.5K /openpool
openpool/ROOT 15.4G 46.3G 18K legacy
openpool/ROOT/rds 15.4G 46.3G 15.3G /
openpool/ROOT/rds/var 102M 46.3G 102M /var
openpool/dump 1.00G 46.3G 1.00G -
openpool/export 311M 46.3G 19K /export
openpool/export/home 311M 46.3G 311M /export/home
openpool/swap 3.91G 50.2G 16K -
storage 220K 134G 21K /storage
storage/onms 57K 134G 21K /storage/onms
storage/onms/log 18K 134G 18K /storage/onms/log
storage/onms/rrd 18K 134G 18K /storage/onms/rrd
storage/snap 18K 134G 18K /storage/snap
I am running an opennms server that stores performance related data in RRDs. they are stored under /opt/opennms/share/rrd/*. As I start to track more and more nodes with more specific OIDs (snmp), disk io is starting to climb steadily. What I am looking to do is move /opt/opennms/share/rrd from openpool and mount it under storage pool (storage/onms/rrd). more specifically, i want to do something like this:
cnjr-opennms>root$ zfs set mountpoint=/opt/opennms/share/rrd storage/onms/rrd
the problem here is i get:
cannot mount '/opt/opennms/share/rrd': directory is not empty
property may be set but unable to remount filesystem
So yes... the truth is there are plenty of directories beyond /opt/opennms/share/rrd/*. I'm just not sure how I can migrate this directory off openpool into storage.
Can anyone shed some light onto this. I am not 100% with zfs just yet but getting there 
I was thinking about symbolic links but i'm not sure thats the best option here.