Explanation
Many Redis and Memcached clusters still use legacy x86-based node types (e.g., cache.r5, cache.m5) even though Graviton-based alternatives are available. In-memory workloads tend to be highly compatible with Graviton due to their simplicity and reliance on standard CPU and memory usage patterns.Unless constrained by architecture-specific extensions or strict compliance requirements, most ElastiCache clusters can be transitioned with no application-level changes. Failing to migrate to Graviton results in unnecessary compute spend and missed opportunities to improve cache efficiency.
Relevant Billing Model
ElastiCache is billed hourly per node, based on:
- Node type and size
- Engine and region
Graviton node types typically deliver up to 40% lower cost for equivalent performance compared to x86.
Detection
- Enumerate all ElastiCache clusters and identify those using x86-based families
- Cross-check with cache.*g instance types available in the region and engine
- Confirm that clusters have no known architecture-specific dependencies
- Analyze memory and CPU usage patterns to validate fit with Graviton
Remediation
- Switch node types to cache.r6g, cache.m6g, or cache.t4g equivalents
- Update provisioning logic to default to Graviton families for new clusters
- Pilot in non-prod or lower-tier environments to validate behavior and latency
- Incorporate architecture reviews into ElastiCache lifecycle and scaling workflows