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JIRA: here [Change the link from KAFKA-1 to your own ticket]

Motivation

Describe the problems you are trying to solve.

Public Interfaces

Briefly list any new interfaces that will be introduced as part of this proposal or any existing interfaces that will be removed or changed. The purpose of this section is to concisely call out the public contract that will come along with this feature.

A public interface is any change to the following:

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Binary log format

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The network protocol and api behavior

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Any class in the public packages under clientsConfiguration, especially client configuration

• org/apache/kafka/common/serialization

• org/apache/kafka/common

• org/apache/kafka/common/errors

• org/apache/kafka/clients/producer

• org/apache/kafka/clients/consumer (eventually, once stable)

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Monitoring

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Command line tools and arguments

Kafka TopicPartitions are replicated on the broker side to different racks. KIP-881 added rack information of clients in partition assignment interface so that the assignment logic can utilize this information to try to assign TopicPartitions to the clients in the same rack as much as possible. The reason why we would like to place TopicPartions to clients in the same rack is because this would avoid cross rack traffic (CRF) which has high costs in terms of latency and money.

The client rack awareness additions in partition assignments also affects how streams can assign its tasks to clients so that cross rack traffic can be avoided as much as possible if partition replicas’ racks won’t always be presented in the client's rack. This design discusses how we can augment current assignment logic to utilize rack information to minimize cross rack traffic with other constraints. In CCloud, currently each partition is replicated to 3 replicas in different AZs, however it’s being changed to replicate to only 2 AZs and other storage like S3 which is where the 2.5x is from.

Public Interfaces

There are no changes in public interfaces.

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Proposed Changes

Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.

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