This topic describes the specifications of master-replica cluster instances of ApsaraDB for Redis Community Edition. These specifications include the memory capacity, maximum number of connections to each instance, maximum bandwidth, and queries per second (QPS) reference value.

Instance types

Instance type InstanceClass that is used in API operations Number of CPU cores Number of shards Maximum number of new connections per second Maximum number of connections ( (in direct connect mode) ) Maximum number of connections ( (in proxy mode) ) Maximum bandwidth value (MB/s) QPS reference value
16 GB cluster instance redis.logic.sharding.2g.8db.0rodb.8proxy.default 16 8 50,000 80,000 500,000 768 640000
32 GB cluster instance redis.logic.sharding.4g.8db.0rodb.8proxy.default 16 8 50,000 80,000 500,000 768 640,000
64 GB cluster instance redis.logic.sharding.8g.8db.0rodb.8proxy.default 16 8 50,000 80,000 500,000 768 640,000
128 GB cluster instance redis.logic.sharding.8g.16db.0rodb.16proxy.default 32 16 50,000 160,000 500,000 1,536 1,280,000
256 GB cluster instance redis.logic.sharding.16g.16db.0rodb.16proxy.default 32 16 50,000 160,000 500,000 1,536 1,280,000
512 GB cluster instance redis.logic.sharding.16g.32db.0rodb.32proxy.default 64 32 50,000 320,000 500,000 2,048 2,560,000

Notes about CPU cores

To ensure service stability, the system reserves a CPU core to process background tasks. In a cluster instance or a read/write splitting instance, the system reserves a CPU core for each data shard or each read replica to process background tasks.

Calculation rules for bandwidth values

  • The bandwidth value in the preceding tables is the bandwidth of the instance. The bandwidth value is the sum of the bandwidth of all shards or nodes in the instance. Each shard has the following bandwidth limits:
    • Community Edition: If the memory of each shard is less than or equal to 1 GB, the maximum bandwidth of each shard is 48 MB/s. If the memory of each shard is greater than 1 GB, the maximum bandwidth of each shard is 96 MB/s.
    • Enhanced Edition (Tair): The maximum bandwidth of each shard is 96 MB/s.
  • If the default proxy endpoint is used by a cluster instance, the upper limit of bandwidth for the cluster instance is 2,048 MB/s. After the upper limit is reached, the bandwidth cannot be increased even if you add more shards to the cluster instance.
    Note To handle excessive network traffic, you can enable the direct connection mode. For more information, see Enable the direct connection mode. The direct connection mode is applicable only to cluster instances. In direct connection mode, the upper limit of the bandwidth is equal to the maximum bandwidth of a single shard multiplied by the number of shards. For example, if a cluster instance contains 128 shards and each shard is allocated with a memory of more than 1 GB, the bandwidth limit is 12,288 MB/s.
  • The bandwidth value applies to the upstream and downstream bandwidths. For example, if the bandwidth of an instance is 10 MB/s, the upstream and downstream bandwidths of the instance are both 10 MB/s.
    Note If your instance has unexpected or scheduled traffic peaks, you can adjust the bandwidth of the instance as needed. For more information, see Adjust the bandwidth of an ApsaraDB for Redis instance.
  • The bandwidth value in the preceding table is the internal bandwidth of the ApsaraDB for Redis instance. The Internet bandwidth is determined by the internal bandwidth and is limited by the bandwidth of the connection between the ApsaraDB for Redis instance and the client. We recommend that you connect to the instance over an internal network to maximize performance.

Calculation rules for connections

Type Description
Maximum number of connections In proxy mode, the maximum number of connections of an instance is 500,000. If the connections reach the upper limit, subsequent connections cannot be established even if you add more shards or nodes.
Maximum number of new connections per second The following example shows how the maximum number of new connections per second affects the maximum number of connections at a specific second: The maximum number of new connections per second of an instance is 10,000. The maximum number of connections of the instance is 50,000. The actual number of connections at the Nth second after the instance starts to run is 12,000. Then, at the (N+1)th second, the maximum number of connections is 22,000, which is calculated by using the following formula: 12,000 + 10,000.
Note If the instance is connected in direct connection mode, connection performance degrades because the proxy server is bypassed. The maximum number of new connections per second for a single data shard is 2,000. For example, if an instance has four data shards, the maximum number of new connections per second is 8,000.

FAQ

Q: Why is the actual bandwidth of my instance different from that described in this topic?

A: The bandwidth of specific instance types may be adjusted after the service is upgraded. If the bandwidth of your instance is different from that described in this topic, you can change your instance specifications by selecting the same instance type to update the bandwidth. The price for your instance remains unchanged after the specifications change. For more information, see Change specifications.