Updated on 2024-04-18 GMT+08:00

Specifications

Kafka Instance Specifications

Kafka instances are compatible with open-source Kafka v1.1.0 and v2.7. Kafka instances are classified into cluster and single-node types. A cluster instance consists of three or more brokers and a single-node one has one broker. Instance specifications are classified based on the ECS flavor. Flavors include kafka.2u4g.cluster.small, kafka.2u4g.cluster, kafka.4u8g.cluster, kafka.8u16g.cluster, kafka.12u24g.cluster, and kafka.16u32g.cluster. Flavors of single-node instances include kafka.2u4g.single.small and kafka.2u4g.single.

For Kafka instances, the number of transactions per second (TPS) is the maximum number of messages that can be written per second. In the following table, transactions per second (TPS) are calculated assuming that the size of a message is 1 KB. For details about TPS performance, see Test Scenarios.

Cluster instances support Kafka versions 1.1.0, 2.7, and 3.x. Single-node instances support Kafka version 2.7.

Table 1 Kafka instance specifications (cluster)

Flavor

Brokers

Maximum TPS per Broker

Maximum Partitions per Broker

Recommended Consumer Groups per Broker

Maximum Client Connections per Broker

Storage Space

Traffic per Broker (MB/s)

kafka.2u4g.cluster.small

3–30

20,000

100

15

2000

300 GB–300,000 GB

40

kafka.2u4g.cluster

3–30

30,000

250

20

2000

300 GB–300,000 GB

100

kafka.4u8g.cluster

3–30

100,000

500

100

4000

300 GB–600,000 GB

200

kafka.8u16g.cluster

3–50

150,000

1000

150

4000

300 GB–1,500,000 GB

375

kafka.12u24g.cluster

3–50

200,000

1500

200

4000

300 GB–1,500,000 GB

625

kafka.16u32g.cluster

3–50

250,000

2000

200

4000

300 GB–1,500,000 GB

750

Table 2 Kafka instance specifications (single-node)

Flavor

Brokers

TPS per Broker

Maximum Partitions per Broker

Recommended Consumer Groups per Broker

Maximum Client Connections per Broker

Storage Space

Traffic per Broker (MB/s)

kafka.2u4g.single.small

1

20,000

100

15

2000

100 GB–10,000 GB

40

kafka.2u4g.single

1

30,000

250

20

2000

100 GB–10,000 GB

100

Instance Specifications and Network Bandwidth

The network bandwidth of a Kafka instance consists of the following:

  1. Network bandwidth used by the instance brokers
  2. Bandwidth of the disk used by the instance brokers. For details, see Disk Types and Performance.

Note:

  • By default, Kafka tests are performed in the tail read scenario (that is, only the latest production data is consumed) instead of the cold read scenario (that is, historical data is consumed from the beginning).
  • The bandwidth of an instance with an old flavor (such as 100 MB/s) is the total network bandwidth of the instance's all brokers.

Traffic calculation of instances with new flavors (such as kafka.2u4g.cluster) is described as follows:

  • The read/write ratio is 1:1.
  • The default number of topic replicas is 3.
  • Total network traffic = Traffic per broker x Broker quantity
  • Total instance traffic = Service traffic + Data replication traffic between brokers

Assume that the current flavor is kafka.2u4g.cluster, the traffic per broker is 100 MB/s, and the number of brokers is 3. What are the total network traffic, maximum read traffic, and maximum write traffic of the instance?

  1. Total network traffic = Traffic per broker x Broker quantity = 100 MB/s x 3 = 300 MB/s
  2. Maximum read traffic = Total instance network traffic/Default number of replicas/2 = 300 MB/s/3/2= 50 MB/s
  3. Maximum write traffic = Total instance network traffic/Default number of replicas/2 = 300 MB/s/3/2 = 50 MB/s

Mapping Between Old and New Flavors

Table 3 compares the old and new Kafka instance flavors.

Table 3 Mapping between old and new Kafka instance flavors

Old Flavor

New Flavor

Flavor

Total Instance Network Traffic

Flavor

Total Instance Network Traffic

100 MB/s

100 MB/s

kafka.2u4g.cluster.small * 3

120 MB/s

300 MB/s

300 MB/s

kafka.2u4g.cluster * 3

300 MB/s

600 MB/s

600 MB/s

kafka.4u8g.cluster * 3

600 MB/s

1200 MB/s

1200 MB/s

kafka.4u8g.cluster * 6

1250 MB/s

Instances with new flavors have the following features:

  • Better performance and cost effectiveness: They use exclusive resources (except for kafka.2u4g.cluster.small). By contrast, old flavors use non-exclusive resources. If the load is heavy, resources conflicts will occur.
  • Latest functions, for example, reassigning partitions, changing the SSL setting, and viewing rebalancing logs.
  • Flexible flavor changes: For example, you can increase or decrease the broker flavor.
  • Flexible disk capacity: Only related to the broker quantity, and not to the flavor.
  • More specification options: A wider range of combinations of broker flavor (over 10,000 MB/s) and quantity are available.
  • More disk type options: General Purpose SSD and Extreme SSD are now available, in addition to the original disk types.

Flavor Selection

  • kafka.2u4g.cluster.small with 3 brokers

    Recommended for up to 6000 client connections, 45 consumer groups, and 60,000 TPS

  • kafka.2u4g.cluster with 3 brokers

    Recommended for up to 6000 client connections, 60 consumer groups, and 90,000 TPS

  • kafka.4u8g.cluster with 3 brokers

    Recommended for up to 12,000 client connections, 300 consumer groups, and 300,000 TPS

  • kafka.8u16g.cluster with 3 brokers

    Recommended for up to 12,000 client connections, 450 consumer groups, and 450,000 TPS

  • kafka.12u24g.cluster with 3 brokers

    Recommended for up to 12,000 client connections, 600 consumer groups, and 600,000 TPS

  • kafka.16u32g.cluster with 3 brokers

    Recommended for up to 12,000 client connections, 600 consumer groups, and 750,000 TPS

Storage Space Selection

Kafka instances support multi-replica storage. The storage space is consumed by all replicas. When creating an instance, specify its storage space based on the expected service message size and the number of replicas.

For example, if the estimated message size is 100 GB, the disk capacity must be at least: 100 GB x Number of replicas + 100 GB (reserved space).

The storage space can be expanded as your service grows.

Topic Quantity

There are limits on the topic quantity and the aggregate number of partitions in the topics. When the partition quantity limit is reached, you can no longer create topics.

The number of topics is related to the maximum number of partitions allowed (see Figure 1) and the specified number of partitions in each topic (see Table 1 and Table 2).

Figure 1 Setting the number of partitions

The maximum number of partitions allowed for an instance with kafka.2u4g.cluster and 3 brokers is 750.

  • If the number of partitions of each topic in the instance is 3, the maximum number of topics is 750/3 = 250.
  • If the number of partitions of each topic in the instance is 1, the maximum number of topics is 750/1 = 750.