ApsaraMQ for Kafka no longer sells instances by topic specification. All existing topic-specification instances are automatically converted to partition specification.
After the conversion, all upgrade and downgrade operations use partition specification only, regardless of how the instance was originally purchased.
How the conversion works
Additionally purchased topics on your existing instance are converted to partitions by using a fixed coefficient. The total partition count after conversion is calculated as follows:
Total partitions = Partitions included in the specification + Additionally purchased topics x Conversion coefficient
The result is rounded up to the nearest integer.
Conversion coefficients
Billing method | Conversion coefficient |
Subscription | 23.913 |
Pay-as-you-go | 45.045 |
Example
A subscription Standard Edition instance has 60 topics (50 included in the specification, 10 additionally purchased) and a bandwidth of 20 MB/s. The specification includes 1,000 partitions.
After conversion:
1,000 + 10 x 40.602 = 1,407 partitions
For partition quotas included in each specification, see Billing rules.
Topic and group quotas after conversion
After the conversion, topic and group quotas are recalculated based on the total partition count:
| Resource | Quota after conversion |
|---|---|
| Topics | Equal to the total number of partitions |
| Groups | Equal to the total number of partitions multiplied by two |
Partition usage that exceeds the converted count
If the partitions currently in use exceed the total partition count after conversion, Alibaba Cloud provides the additional partitions at no cost.
For example, if the conversion yields 1,000 partitions but 1,100 are in use, Alibaba Cloud covers the extra 100 partitions free of charge.