This page gives an overview of single-zone instances for Memorystore for Redis Cluster.
For instructions on provisioning a single-zone instance see Create a single-zone instance .
By default, Memorystore for Redis Cluster distributes an instance's nodes evenly among available zones. For diagrams that show how nodes are distributed with this setup, see High availability and replicas .
Alternatively, you can choose to create a single-zone instance. Single-zone instances have lower latency than multi-zone instances because you can place your clients in the same zone as the Redis nodes and avoid cross-zone communication.
You choose the zone distribution mode (single-zone or multi-zone) during instance creation. After it's created, the zone distribution mode can't be changed.
When choosing between a multi-zone instance and a single-zone instance, you should consider your application's tolerance for downtime or data loss if an unexpected zonal outage occurs.
If an unexpected outage impacts the zone where your single-zone instance located, you can lose connectivity to all the nodes in the instance and experience data loss if either persistence or high-availability is not enabled. Alternatively, if an unexpected outage impacts one of the zones of a multi-zone instance, only a portion of the nodes may become unavailable.
If you connect to a single-zone instance from a client in the same zone, then you aren't charged for Consumer Data Processing . For more information, see Network pricing .
Although we recommend provisioning a multi-zone instance with High Availability , you should use the following recommendations for single-zone instances if they apply to you:
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If you you choose to provision a single-zone instance, you should enable replicas. Replicas reduce shard hotspots and make shards more resilient against single-node failures.
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If you choose to provision an instance without replicas, you should still use a single-zone instance. For more information, see Choose a single-zone instance if your instance doesn't use replicas .
Single-zone instance diagram example
