Multi-availability zone architecture can provide redundancy for a more resilient Redis infrastructure. ElastiCache instances can be configured in clusters that cross availability zones. For more information, see the AWS documentation.
References:
https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/AutoFailover.html
In AWS Console -
In Terraform -
References:
https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/RegionsAndAZs.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticache_cluster#az_mode