Modifying Kafka Instance Specifications

Scenario

After creating a Kafka instance, you can increase its storage space, bandwidth (only for old specifications), and broker quantity (only for new specifications).

Distinguishing between old and new specifications:

Old specifications: In the instance list, the instance specification is displayed as bandwidth (for example, 100 MB/s).
New specifications: In the instance list, the instance specification is displayed as the ECS flavor multiplied by the number of brokers (for example, kafka.2u4g.cluster*3 brokers).

Figure 1 Instance list
Click to enlarge

Impact of Specification Modification

It takes 5 to 10 minutes to modify specifications on one broker. The more brokers, the longer time the modification takes.

**Table 1** Impact of specification modification
Modified Object	Impact
Bandwidth or broker quantity	Increasing the bandwidth or adding brokers does not affect the original brokers or services. When you increase the bandwidth or change the broker quantity, the storage space is proportionally expanded based on the current disk space. For example, assume that the original number of brokers of an instance is 3 and the disk size of each broker is 200 GB. If the broker quantity changes to 10 and the disk size of each broker is still 200 GB, the total disk size becomes 2000 GB. New topics are created on new brokers, and the original topics are still on the original brokers, resulting in unbalanced partitions. You can reassign partitions to migrate the replicas of the original topic partitions to the new brokers.
Storage space	You can expand the storage space 20 times. Storage space expansion does not affect services.

Modifying Kafka Instance Specifications

Log in to the console.
Click in the upper left corner to select a region.

Select the region where your Kafka instance is located.
Click and choose Application > Distributed Message Service for Kafka to open the console of DMS for Kafka.
In the row containing the instance for which you want to modify the specifications, choose More > Modify Specifications in the Operation column.
Specify the storage space, number of brokers, or bandwidth as required.
To modify old specifications, perform the following steps:
- Increase the bandwidth.
  Specify a new bandwidth and click Next. Confirm the configurations and click Submit.
  
  View the new bandwidth of the instance in the Specifications column in the instance list.
  
  After increasing the bandwidth, add the IP address of the new broker to the client connection configuration to improve reliability.
- Expand the storage space.
  Specify a new storage space and click Next. Confirm the configurations and click Submit.
  
  View the new storage space in the Used/Available Storage Space (GB) column in the instance list.
To modify new specifications, perform the following steps:
- Expand the storage space.
  For Change By, select Storage. For Storage Space per Broker, specify a new storage space, and click Next. Confirm the configurations and click Submit.
  
  View the new storage space (Storage space per broker x Number of brokers) in the Used/Available Storage Space (GB) column in the instance list.
- Add brokers.
  For Change By, select Brokers. Then, enter the number of brokers and click Next. Confirm the configurations and click Submit.
  
  View the number of brokers in the Specifications column in the instance list.
  
  After adding brokers, add the IP addresses of the new brokers to the client connection configuration to improve reliability.