For AWS Aurora disk related (operations, latency, throughput) graphs are populated directly from CloudWatch. However, all data points are missing, because metrics are stored within RDSOSMetrics when enhanced monitoring is enabled.
This can be fetched directly from Prometheus, as rds_exporter fetches this (from /enhanced route).
[root@0abb803d12bc opt]# curl 127.0.0.1:9042/enhanced | grep -i 'read\|write'
# HELP node_vmstat_pswpin Number of kilobytes the system has swapped in from disk per second (disk reads).
# HELP node_vmstat_pswpout Number of kilobytes the system has swapped out to disk per second (disk writes).
# HELP rdsosmetrics_diskIO_diskQueueDepth The number of outstanding read/write requests waiting to access the disk.
# HELP rdsosmetrics_diskIO_readIOsPS The number of read operations per second. This metric is not available for Amazon Aurora.
# TYPE rdsosmetrics_diskIO_readIOsPS gauge
# HELP rdsosmetrics_diskIO_readLatency The average amount of time taken per disk I/O operation.
# TYPE rdsosmetrics_diskIO_readLatency gauge