This topic describes the terms of ApsaraDB for Redis.

Term Description
Redis ApsaraDB for Redis is a high-performance, key-value storage system that supports caching and storage. The system is developed based on BSD open source protocols.
Instance ID Each instance corresponds to a user space, and serves as the basic unit of the ApsaraDB for Redis service. ApsaraDB for Redis has limits on instance specifications, such as connections, bandwidth, and CPU capacity. These limits vary based on different instance types. You can view the IDs of your purchased instances in the console.
Master-replica instance The ApsaraDB for Redis instance that contains a master-replica architecture. The master-replica instance provides limited capacity and performance. However, you can change a master-replica instance to an instance of another type, such as a cluster instance or a read/write splitting instance.
Cluster instance An ApsaraDB for Redis instance that runs in a cluster architecture with scalability. Cluster instances provide higher scalability and performance. However, these instances also provide limited features.
Endpoint The host address that is used to connect to ApsaraDB for Redis. The endpoint is displayed as a domain name. To obtain the endpoint, choose Instance Information > Connection Information.
Connection password The password used to connect to ApsaraDB for Redis. The password is in the format of Instance ID:custom password. For example, if you set the password to 1234 when you purchase an instance and the allocated instance ID is xxxx, the connection password is xxxx:1234.
Eviction policy This is the same as the Redis eviction policy. For more information, see Using Redis as an LRU cache.
DB The database in ApsaraDB for Redis. Each ApsaraDB for Redis instance supports 256 databases: DB 0 to DB 255. By default, data is written into DB 0.