Add DRR to the monitoring screen #2705
Description
Scylla allows to compress the data at rest, which provides a significant cost reduction for our customers. The customer get s the value, but it is not presented.
We would like to show the value that Scylla provides the user.
The information should be displayed:
DRR: 2.2:1
You saved 45TB
With tooltip that explains that DRR = Data Reduction Rate
The information can be initially displayed in the DCs Data panel.
If possible with a link to see the compression per table.
The information is kept per table.
It should be gathered to monitoring system, aggregated and the DRR and size saved should be calculated.
Metrics:
scylla_table_uncompressed_data_size_bytes - per node+table - logical size before compression
scylla_table_compressed_data_size_bytes - per node+table - logical size after compression
Prometheus:
Cluster compression ratio: sum(scylla_table_uncompressed_data_size_bytes) / sum(scylla_table_compressed_data_size_bytes)
Cluster storage savings: sum(scylla_table_uncompressed_data_size_bytes) - sum(scylla_table_compressed_data_size_bytes)