Collecting object I/O level diagnostics

The following object I/O level diagnostic tables collect data on object I/O statistics:

object_io

Per node recent latency metrics by keyspace and table.
object_read_io_snapshot

Per node recent latency metrics, broken down by keyspace and table and orders data by mean read latency.
object_write_io_snapshot

Per node recent latency metrics, broken down by keyspace and table and orders data mean write latency.

Procedure

To enable the collection of this data:
Edit the dse.yaml file.
In the dse.yaml file, set the enabled option for resource_level_latency_tracking_options to true.
```
resource_level_latency_tracking_options:
    enabled: true
    refresh_rate_ms: 10000
```
(Optional) To control how often the statistics are refreshed, increase or decrease the refresh_rate_ms option in dse.yaml.

The refresh_rate_ms specifies the length of the sampling period, that is, the frequency with which this data is updated.