Hi guys, just wanted to add I’ve had the same issue as mentioned here. Installed rrdtool 1.6 from OpenNMS repo and now getting graph errors so I guess this route is to be avoided.
Looks like I’ll have to bite the bullet and try from source or fall back on 1.4.
Source is simple to install from 
So I have the opennms 1.6.0 installed on my “all-in-one” box and my graphs are fine…
This week I’ve been trying to set up distributed poller on some test VM’s though (also CentOS 6) and installed the same package, I can’t be certain yet but kkrumm pointed me to this thread and suggested I try a compile from source instead to rule out the opennms 1.6.0 package.
When I try running the poller it eventually freezes at some point on one of the RRD commands… and nothing is ever getting written to my actual remote rrdcached server. Tomorrow I can try and compile from source instead of using the opennms 1.6.0 package if you guys think that might help. Also open to suggestion on if there’s anything else I might need to check as to why no files are getting written to the remote rrdcached server. The goal was to use 1.6.0 so we didn’t need shared NFS since supposedly 1.6.0 allows remote file writing I’ve read on your docs.
Update - looks like it may have just been a group permissions error. Only change we did this morning troubleshooting was adding chown g+w for librenms to the rrdcached servers /opt/librenms/rrd folder and then I tried letting the poller server run again and BAM I had files creating just fine. (still on the OpenNMS 1.6.0 rrdtool install for CentOS 6)