Unnecessary Multi-AZ Deployment for ElastiCache in Non-Production Environments

Service Category

Databases

Cloud Provider

AWS

Service Name

AWS ElastiCache

Inefficiency Type

Misconfigured Redundancy

Explanation

In non-production environments, enabling Multi-AZ Redis clusters introduces redundant replicas that may not deliver meaningful business value. These replicas are often kept in sync across Availability Zones, incurring both compute and inter-AZ data transfer costs. For development or test clusters that can tolerate occasional downtime or data loss, a single-AZ deployment is typically sufficient and significantly less expensive.

Relevant Billing Model

Billed per node-hour, with separate charges for primary and replica nodes; cross-AZ replication incurs additional data transfer charges.

Detection

Check if ElastiCache Redis clusters in non-production accounts or environments are configured with multiple nodes across different Availability Zones
Confirm whether replication groups have replicas where fault tolerance is not required
Review whether the cluster supports ephemeral workloads that don’t require HA or persistence
Assess whether production-level SLAs or failover requirements apply to these environments

Remediation

Reconfigure ElastiCache Redis clusters in non-production environments to use single-node, single-AZ deployments
If persistence is not needed, consider using Memcached instead of Redis to further reduce costs
Tag clusters appropriately to distinguish between environments and enforce automated guardrails

Relevant Documentation

Amazon ElastiCache Pricing
ElastiCache Best Practices

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