AnalyticDB for MySQL Elastic Cluster utilizes an architecture that separates storage resources from computing resources. An elastic I/O unit (EIU) is the unit of data that measures the storage performance of AnalyticDB for MySQL Elastic Cluster. You can use EIUs to separately scale out storage resources.
Scenarios
- Data import: You have purchased a small amount of computing resources. A large amount of data is written, which causes I/O bottlenecks of storage nodes. In this case, you must separately scale out your storage resources.
- Point query: You have purchased a small amount of computing resources. CPU becomes the bottleneck of storage resources. In this case, you must separately scale out your storage resources.
EIU-based storage performance metrics
Storage performance metrics are based on a mixture of I/O usage, space usage, and CPU utilization. Storage performance metrics are in proportion to the number of EIUs. The following table describes storage performance metrics of each EIU.
| Metric | Maximum value |
|---|---|
| Hot data storage space | 4 TB |
| IOPS | 16,800 to 50,000 |
| Throughput | 350 MB/s |
| CPU | 24 cores |
Determine the number of EIUs
- When you create a cluster
- AnalyticDB for MySQL provides free EIUs based on the computing resources you purchase. You do not need to specify the number of EIUs.
- When you scale out a cluster
- When you scale out a cluster, you can increase the number of EIUs to improve the data read/write capabilities of the cluster. For more information about the billing method of EIUs that are scaled out, see Billing methods and prices.