we have a lot of UNKNOWNs in Icinga from:
Varnishkafka Delivery Errors per minute
they are either "UNKNOWN: No valid datapoints found" or "UNKNOWN: More than half of the datapoints are undefined"
I reopened T76342 for this, but:
< ottomata> mutante: i think that is a new issue, that one was for check_ganglia. this one is from graphite, and the data is really not in graphite