Help Center/ Distributed Cache Service/ Drawer/ Buying a DCS Instance/ Replicas
Updated on 2025-05-28 GMT+08:00
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Replicas

Parameter Explanation

A replica refers to a node of a DCS instance. It can be a master node or a standby node.

A two-replica instance has one master node and one standby node. A three-replica instance has one master node and two standby nodes. If the master node is faulty, a master/standby switchover is performed to restore services.

A single-node instance has one replica.

FAQs

How Do I Select the Number of Replicas?

  • Single-node

    There is only one node. There is only one replica and this quantity cannot be customized.

  • Master/Standby

    There are two replicas by default. A master/standby basic edition DCS Redis instance can have 2 to 10 replicas. Master/Standby professional edition instances can have only 2 replicas.

    Adding replicas (standby nodes) increases instance reliability without affecting its performance. If a master/standby instance is used for read/write splitting, its read performance can be improved by adding replicas.

  • Read/Write splitting

    By default, read/write splitting is implemented on the server (the master node for write requests and the replicas for read requests). Each instance can have two (default) to six replicas.

    Adding replicas increases instance reliability and read performance.

  • Proxy Cluster

    There are two replicas by default. This quantity cannot be customized.

  • Redis Cluster

    There are two replicas by default. Range: 1–5.

    Use at least two replicas for reliability. A single-replica instance only has the master node and cannot ensure data reliability and SLA if the physical server is faulty.

Parent Topic: Buying a DCS Instance