Term Explanation

• Partition: It refers to the basic throughput unit. A partition provides 1 MB/sec data input throughput and 2 MB/sec output throughput. You can specify the number of partitions required for the data stream according to the throughput requirements, and make payments for each partition. If the service time is less than one hour, the service is free.
• Record: It refers to the billing unit of the Kafka data stream, which is calculated according to 25 KB payload and charged per million records. If the data stream has less than one million records, it is charged according to the actual records. For example, a 5 KB message is charged as one record, a 49 KB message is charged as two records, and a 1 MB message is charged as 40 records. Both read and write messages are counted as records.

For more information on Baidu Messaging System, please see the [Product Description](Kafka/Product Descripition/Introduction.md) and [Getting Started Guide](Kafka/Getting Started/Operating Process.md).

Billing

Baidu Messaging System adopts the postpaid method, which means that you are charged according to your actual usage in real time. That is to say that you only make payments for the used partitions and transmitted messages.

Before making a purchase, you need to ensure that the total of your account balance and available vouchers is greater than or equal to 50 CNY.

Message transmission is charged with the stepwise accumulation method.

Note: After a topic is created, it is regarded that partitions are in use, and the partition billing item starts to work. After a topic is created, if no messages are transmitted, the message transmission billing item does not work.

Billing Formula

Cost=Unit price x Number of partitions x Service time+Unit price x Transmitted messages

Billing examples

For example, 200 million write requests and 300 million read requests occur in the website per hour, and each request generates a message of 1KB, which is written into the Baidu Messaging System.

1. Calculate the write traffic per second: 200,000,000/60/60x1/1,024=55 (after the result has been rounded up), that is, the write traffic per second is around 55 MB/sec.
2. Calculate the read traffic per second: 300000000/60/60x1/1,024=82 (after the result has been rounded up), that is, the write traffic per second is around 82MB/sec.
3. If a partition provides the 1 MB/sec data input throughput and 2 MB/sec output throughput, calculate the number of the required partitions : max {55/1, 82/2}=55, that is, the number of the required partitions is 55.
4. Calculate the required cost of message transmission: If the total of read and write requests reaches 500 million, calculate the cost with the stepwise accumulation method: 0.007x20,000,000/1,000,000+0.006x300,000,000/1,000,000=3.2 CNY
5. Take the North China region as an example. The required cost per hour is 0.06x55+3.2=6.5, which means that it takes only 6.5 CNY per hour.

Reminders of Insufficient Balance and Arrear-related Measures

• Reminders of insufficient balance:

  • If your account balance (including available vouchers) cannot pay your bill for the next 3 days based on your bill for the last 3 days, the system sends you a renewal reminder.
  • If your account balance (including available vouchers) cannot pay your bill for the next day based on your bill for the last day, the system sends you a renewal reminder.

• Arrear-related measures:

  • The system is designed to check hourly (Beijing Time) whether your account balance can pay your Kafka bill. For example, the system checks whether your account balance can pay your bill from 10:00 am to 11:00 am at 11:00 am Beijing Time. If it cannot, the system believes that your account is in arrears, and sends you a renewal reminder.
  • After that, your service is suspended immediately, and the system sends you a service suspension notice due to arrears. The data is reserved for you for 1 day, when you can top up your account. If you failed to do so, the resources may be released. To make sure you have a good service experience, it is recommended that you should keep your account balance sufficient to pay your bill when using Kafka.