Network Bandwidth Ceiling for EBS-backed RDS
warningRDS MySQL/MariaDB instances use EBS over the network, and network throughput limits can cap realized IOPS below provisioned levels. Even with high provisioned IOPS, network saturation (especially on smaller instance classes) prevents the database from achieving expected disk performance.
Monitor NetworkReceiveThroughput and NetworkTransmitThroughput against instance class bandwidth limits (e.g., 1 Gbps = ~8000 IOPS at 16KB pages). If provisioned IOPS exceed network capacity and you observe high DiskQueueDepth with elevated ReadLatency/WriteLatency, the network is the bottleneck. Look for correlation between network throughput approaching limits and IOPS plateauing below provisioned values.
Upgrade to a larger instance class with higher network bandwidth if provisioned IOPS consistently exceed network capacity. Review read/write balance and consider read replicas to offload read traffic. For extremely read-heavy workloads, optimize queries and increase InnoDB buffer pool to reduce disk reads. Evaluate storage type—ensure you're using Provisioned IOPS (io1/io2) storage if throughput is critical.