Following metrics values does not match, please explain what it means?
scylla_storage_proxy_coordinator_foreground_reads
scylla_storage_proxy_coordinator_read_latency_count
Does not match what? 
?
Anyhow if you install scylla monitoring ( ScyllaDB Monitoring Stack | ScyllaDB Docs ), in dashboard of monitoring you can hover your mouse above (i) icon to get explanation of metrics, below are:
scylla_storage_proxy_coordinator_foreground_reads
- Foreground reads are reads that weren’t acknowledged yet to the application. For instance, if a single replica responded and two are needed due to the consistency level. This metric represents a queue size, not a rate. High values here correlate with increased read latencies.
( scylla-monitoring/grafana/scylla-detailed.template.json at master · scylladb/scylla-monitoring · GitHub )
scylla_storage_proxy_coordinator_read_latency_count
- this is used for calculating Reads rate, it’s part of:
HELP scylla_storage_proxy_coordinator_read_latency The general read latency histogram
TYPE scylla_storage_proxy_coordinator_read_latency histogram
you can get other help for metrics by doing on Scylla node:
curl http://<LISTEN_ADDRESS_OF_SCYLLA>:9180/metrics