Term | Description |
instance ID | A basic unit of Tair (Redis OSS-compatible). Each instance corresponds to a user space. Tair 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 instance IDs in the Tair console. |
deployment mode | Cloud-native: uses a new-generation management architecture that provides better scalability and elasticity. This architecture serves as a basis for subsequent development. Classic: uses the conventional management architecture.
For more information, see Comparison between cloud-native instances and classic instances. |
instance type | High availability: uses a master-replica architecture in which two or more nodes are deployed to provide high service reliability. Master node: serves your workloads. Each master-replica instance contains only one master node. Replica node: provides high availability (HA). If the master node fails, the system switches workloads over to the replica node that has the most complete and up-to-date data within 30 seconds. This ensures smooth business operations.
Standalone: contains only a single data node. No replica nodes are provided to synchronize data in real time. Standalone instances are suitable for cache-only scenarios that do not require high data reliability. Standalone instances are available at a relatively low price.
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primary (secondary) zone node | This term applies to instances deployed across multiple zones. In normal cases, the master node, referred to as the primary zone node, is deployed in the primary zone. Replica nodes, referred to as secondary zone nodes, are deployed in the secondary zone. For more information, see Regions and zones. If one master node and two replica nodes are configured for an instance, one master node and one replica node are deployed in the primary zone. The other replica node is deployed in the secondary zone. If one master node and three or more replica nodes are configured for an instance, you must deploy at least one master node and one replica node in the primary zone. Then, you can deploy the remaining replica nodes in the primary zone or the secondary zone based on your business requirements.
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storage medium | Tair instances support three storage mediums. The storage mediums have the following features and use scenarios: Redis Open-Source Edition: stores data in memory to provide high-performance and low-latency services. Redis Open-Source Edition is suitable for the use scenarios of open source Redis. DRAM-based instance: stores data in memory and uses a multi-threaded model. A DRAM-based instance provides approximately three times the performance of a Redis Open-Source Edition instance that has the same specifications. DRAM-based instances support features such as semi-synchronous replication, point-in-time recovery (PITR), and Global Distributed Cache, and provide multiple enhanced data modules to simplify development. DRAM-based instances are suitable for scenarios that require ultra-high performance or active geo-redundancy. Persistent memory-optimized instance: stores data in persistent memory to provide command-level persistence capabilities. Persistent memory-optimized instances are suitable for scenarios that require high performance and data consistency. ESSD/SSD-based instance: stores data 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 a Redis Open-Source Edition instance at a cost as low as 15% of a Redis Open-Source Edition instance. ESSD/SSD-based instances are suitable for scenarios that require moderate performance and high cost-effectiveness.
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version compatibility | Tair is compatible with 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 the eviction policy of Redis. For more information, see Key eviction. |
DB | Each Tair instance can contain up to 256 databases: DB 0 to DB 255. By default, data is written to DB 0. |
