As the subject says. One of drives has no RRD graphs in the Diskstats Plugin. All that shows is the "frown face."
I tried using OMV Firstaid to check the RRD graphs. It seems that a huge number have future dates so I deleted them. All this did was erase the existing data and present empty graphs until the next time it polled the disks. This did not fix the frowns displayed on the one disk.
Looking in /etc/collectd/collectd.conf.d/disk.conf I see that the disk in question is not listed. I added it by hand and I'll see what happens after running:
omv-salt deploy run monit