Tair (Redis® OSS-Compatible):FAQ about bandwidth

Is the bandwidth of an instance limited?

Yes. All Tair and Redis Open-Source Edition instances have bandwidth limits, and the maximum value varies by instance type.

To find the limit for your instance, go to the Instance Information page in the Tair console or call the DescribeIntranetAttribute API operation. For a full list of limits by instance type, see Instance types and FAQ.

Does the bandwidth limit apply to internal network or public network connections?

The bandwidth limit is per shard and applies regardless of how clients connect. Whether traffic flows over an internal network or the public internet, the same limit applies.

For example, a tair.rdb.1g instance has a bandwidth limit of 96 MB/s per shard. That limit holds for both internal network and public network connections.

Does the bandwidth limit apply to upstream or downstream traffic?

Both. The bandwidth value covers upstream and downstream traffic equally. If the limit is 192 Mbps (24 MB/s), both upstream and downstream are capped at 192 Mbps (24 MB/s).

How is bandwidth calculated for cluster and read/write splitting instances?

The total bandwidth equals the sum of bandwidths across all shards or replicas.

For example, a cluster instance with four shards of the redis.shard.with.proxy.small.ce type—each with 24 MB/s bandwidth—has a total bandwidth of 96 MB/s.

How do I increase bandwidth?

You can increase bandwidth using one of the following methods:

• Cluster or read/write splitting instances: Add shards or read replicas to scale total bandwidth. See Adjust the number of shards for a cluster and Enable read/write splitting.

  Note

  Cluster instances in proxy mode and read/write splitting instances have a maximum total bandwidth of 2,048 Mbit/s. Adding more shards beyond this limit does not increase bandwidth. Cluster instances in direct connection mode have no overall bandwidth limit.

• All instance types except Tair ESSD-based instances: Manually adjust the bandwidth. See Manually increase the bandwidth of an instance.

• Redis Open-Source Edition instances and Tair Memory-optimized instances in classic mode: Enable bandwidth Auto Scaling to adjust bandwidth automatically. See Enable bandwidth Auto Scaling.

Am I charged for bandwidth or data transfer?

Tair does not charge data transfer fees.

Bandwidth is free unless you manually adjust it or enable bandwidth Auto Scaling. If you do adjust the bandwidth, fees apply. See Billable items for pricing details.

Why does my instance bandwidth differ from the documented value?

If your instance is a Redis Open-Source Edition cloud-native instance created before June 20, 2023, its bandwidth may not match the current documentation. Alibaba Cloud increased the default bandwidth for Redis Open-Source Edition cloud-native instances on that date. The documentation reflects the updated values.

The new default applies automatically to instances created or modified on or after June 20, 2023. To apply the updated bandwidth to an existing instance, change its configuration—for example, upgrade the specifications or change the architecture. See [Notice] Default bandwidth is increased for Redis Community Edition cloud-native instances for details.

How do I find out which key is consuming the most bandwidth?

Tair does not provide a feature to identify which key or command uses the most bandwidth. For steps to diagnose and resolve high traffic usage, see Troubleshoot high traffic usage on an instance.