Term | Description |
instance ID | A basic unit of ApsaraDB for Redis. Each instance corresponds to a user space. Redis has limits on instance configurations, such as the number of connections, bandwidth, and CPU power. The limits vary based on different instance types. You can view the list of your instance IDs in the Tair console. |
deployment mode | Cloud-native (cloud disk-based): uses a new-generation management architecture that provides better scalability. This architecture serves as a basis for subsequent development. Classic (local disk-based): uses the conventional architecture based on physical machines.
For more information, see Comparison between cloud-native instances and classic instances. |
instance type | High availability: uses a master-replica architecture. The master node serves your workloads, and the replica node works in hot standby mode to ensure high availability. If the master node fails, the system fails the workloads over to the replica node within 30 seconds after the failure occurs. This ensures the high availability of your instance. Standalone: contains only a single data node. No replica nodes are provided to synchronize data in real time. Standard standalone instances are suitable for cache-only scenarios that do not require high data reliability. Standard standalone instances are available at a relatively low price.
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storage medium | Tair instances support three storage mediums. The storage mediums have the following characteristics and use scenarios: DRAM: DRAM-based instances use the multi-threading model. A DRAM-based instance delivers three times the performance of a Community Edition instance that has the same specifications, and provides a variety of enhanced data structures to simplify development. This storage medium is suitable for scenarios that require ultra-high performance or active geo-redundancy. Persistent memory: Data is stored in persistent memory to provide command-level persistence capabilities. This storage medium is suitable for scenarios that require high performance and data consistency. ESSDs and SSDs: Data is stored in Enterprise SSDs (ESSDs) or standard SSDs to provide command-level persistence capabilities and massive storage capacity. An ESSD/SSD-based instance delivers approximately 60% of the performance of an ApsaraDB for Redis Community Edition instance at a cost that can be as low as 15% of the cost of an ApsaraDB for Redis Community Edition instance. This storage medium is suitable for scenarios that require moderate performance and high cost-effectiveness.
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version compatibility | Tair is compatible with open source Redis versions such as Redis 7.0, Redis 6.0, Redis 5.0, and Redis 4.0. |
eviction policy | The eviction policy that is used in Tair is the same as that of open source Redis. For more information, see Key eviction. |
DB | Each ApsaraDB for Redis instance can contain up to 256 databases: DB 0 to DB 255. By default, data is written to DB 0. |