Amazon ElastiCache adds thirteen new Amazon CloudWatch metrics for network capacity planning and engine diagnostics

Amazon ElastiCache

Amazon ElastiCache customers can now detect network throttling, memory fragmentation, and connection exhaustion using thirteen new Amazon CloudWatch metrics for node-based clusters. These metrics enable monitoring of host-level and engine-level diagnostics directly from CloudWatch without running INFO commands on individual nodes or calculating baselines from raw byte counters.

Network capacity

• NetworkBaselineUsageInPercentage: Network utilization relative to instance baseline.
• NetworkBaselineUsageOutPercentage: Network utilization relative to instance baseline.
• NetworkBaselineMaxUsageInPercentage: Per-second bursts that averaged metrics can hide.
• NetworkBaselineMaxUsageOutPercentage: Per-second bursts that averaged metrics can hide.

Memory health

• UsedMemoryDataset: Memory consumed by actual stored data excluding engine overhead.
• AllocatorFragmentationBytes: Fragmentation that the activedefrag parameter can address.
• AllocatorFragmentationRatio: Fragmentation that the activedefrag parameter can address.
• MajorPageFaults: OS-level page faults indicating memory pressure beyond what the engine can surface.

Connectivity health

• BlockedConnections: Connections waiting on blocking commands.
• RejectedConnections: Connections turned away when the maxclients limit is reached.

Pub/sub workloads

• PubSubChannels: Active classic channels on each node.
• PubSubShardChannels: Active sharded channels on each node.

Command throughput

• ProcessedCommands: Total command throughput across all command types.

What to do

• View the new metrics in the ElastiCache console monitoring tab or in the AWS/ElastiCache namespace in the CloudWatch console.
• Consider switching to sharded pub/sub to scale horizontally if classic channel counts are growing with utilization.
• Raise maxclients or diagnose client-side connection pool leaks if RejectedConnections is non-zero.

Source: AWS release notes

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