skills/redis-development/rules/cluster-read-replicas.md

title	impact	impactDescription	tags	description	alwaysApply
Use Read Replicas for Read-Heavy Workloads	MEDIUM	Scales read throughput without adding primary nodes	cluster, replicas, read-scaling, high-availability	Use Read Replicas for Read-Heavy Workloads	true

Use Read Replicas for Read-Heavy Workloads

For read-heavy workloads, distribute reads across replicas to reduce load on primaries.

Correct: Configure replica reads in Redis Cluster.

from redis.cluster import RedisCluster

rc = RedisCluster(
    host='localhost',
    port=6379,
    read_from_replicas=True  # Distribute reads to replicas
)

# Writes go to primary
rc.set("key", "value")

# Reads can be served by replicas (eventually consistent)
value = rc.get("key")

Correct: Use replica reads in standalone replication setup.

from redis import Redis

# Connect to primary for writes
primary = Redis(host='primary-host', port=6379)

# Connect to replica for reads
replica = Redis(host='replica-host', port=6379)

# Write to primary
primary.set("key", "value")

# Read from replica (eventually consistent)
value = replica.get("key")

Considerations:

• Replica reads are eventually consistent
• Don't read from replicas for data that was just written
• Use for read-heavy, slightly-stale-OK workloads (caches, analytics, dashboards)

Reference: Redis Replication