The following two queries show the total capacity of bytes in the cluster and the number of bytes used. They can be used to generate pie chart in Grafana to show the percentage of used space. Note that these counters show the raw capacity before replication:

    maxSeries(collectd.mon*.ceph.mon.mon*.ceph_bytes.Cluster.osdBytes)

    maxSeries(collectd.mon*.ceph.mon.mon*.ceph_bytes.Cluster.osdBytesUsed)