This topic describes the specifications of read/write splitting instances of ApsaraDB for Redis Community Edition. These specifications include the memory capacity, maximum number of concurrent connections to each instance, maximum bandwidth, and QPS reference value.

## Instance specifications

Instance type | InstanceClass (API operation) | Number of read replicas | Bandwidth (MB/s) | Maximum number of new connections per second | Maximum number of concurrent connections | QPS reference value |
---|---|---|---|---|---|---|

1 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.small.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

1 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.small.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

1 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.small.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

2 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.mid.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

2 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.mid.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

2 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.mid.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

4 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.stand.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

4 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.stand.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

4 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.stand.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

8 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.large.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

8 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.large.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

8 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.large.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

16 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.2xlarge.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

16 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.2xlarge.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

16 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.2xlarge.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

32 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.4xlarge.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

32 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.4xlarge.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

32 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.4xlarge.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

64 GB read/write splitting instance (1 primary node, 1 read replica) | redis.logic.splitrw.8xlarge.1db.1rodb.4proxy.default | 1 | 192 | 20000 | 20000 | 200000 |

64 GB read/write splitting instance (1 primary node, 3 read replicas) | redis.logic.splitrw.8xlarge.1db.3rodb.4proxy.default | 3 | 384 | 40000 | 40000 | 400000 |

64 GB read/write splitting instance (1 primary node, 5 read replicas) | redis.logic.splitrw.8xlarge.1db.5rodb.6proxy.default | 5 | 576 | 50000 | 60000 | 600000 |

## Bandwidth calculation rules

- If network resources are sufficient, Apsaradb for Redis instances do not have bandwidth limits. However, if network resources are insufficient, the limits in the above table take effect.
- The bandwidth value in the table represents the bandwidth of the instance, that is, the total bandwidth of all shards or nodes in the instance.
- The maximum bandwidth of an instance (including all shards or nodes) is 2,048 MB. Bandwidth does not increase even if the number of shards or nodes increases.
- The bandwidth applies to the upstream bandwidth and the downstream bandwidth respectively. If the bandwidth of an instance is 10 MB/s, the upstream and downstream bandwidth of the instance are both 10 MB/s.
- The bandwidth in the table is the internal bandwidth of the Redis instance. The Internet bandwidth is determined by the internal bandwidth and is limited by the bandwidth of the connection between the Redis instance and the client. We recommend that you connect to the instance over an internal network to maximize its performance.

## Connection number calculation rules

- The following example explains the maximum number of new connections per second: If the maximum number of new connections per second of an instance is 10000, the actual number of concurrent connections at the Nth second after the instance starts to run is 12000, at the (N+1)th second, the actual number of concurrent connections is 22000, then the number of new connections within that second is 22000-12000=10000, which is not greater than the maximum number of new connections per second.
- The maximum number of new connections per second and the maximum number of concorrent connections are the sum of the corresponding values of all shards or nodes in the instance. After 500000 is reached, the maximum number of concorrent connections is not increased even if the number of shards or nodes is increased.