Resilience

DCS provides a three-level reliability architecture and uses cross-AZ DR, intra-AZ instance DR, and instance data replication to ensure service durability and reliability.

**Table 1** DCS reliability architecture
Reliability Solution	Description
Cross-AZ DR	DCS provides master/standby, Redis Cluster, and Proxy Cluster instances that support cross-AZ DR. When an AZ is abnormal, the instances can still provide services.
Intra-AZ instance DR	A master/standby, Redis Cluster, or Proxy Cluster DCS instance has multiple nodes for instance-level DR within an AZ. If the master node is faulty, services are quickly switched to a standby node to ensure uninterrupted DCS services.
Data DR	Data DR is implemented through data replication.