This topic describes the limits and performance metrics of Data Online Migration.
Resource quotas
Data Online Migration limits the number of resources such as migration tasks, data addresses, proxies, and channels.
Resource | Maximum number per region |
Migration tasks | 500 |
Data addresses | 1000 |
Proxies | 100 |
Channels | 100 |
Concurrent migration tasks
Data Online Migration limits the number of tasks that can run concurrently. If this limit is exceeded, new tasks will fail to start. The following table lists the limits for each region.
Region | Concurrent tasks |
China (Hangzhou) | 10 |
China (Shanghai) | 10 |
China (Beijing) | 10 |
China (Ulanqab) | 10 |
China (Shenzhen) | 10 |
China (Chengdu) | 10 |
China (Hong Kong) | 10 |
Japan (Tokyo) | 5 |
Singapore | 5 |
Germany (Frankfurt) | 5 |
US (Virginia) | 5 |
Migration tasks in the following states are considered running: Starting, Preparing, Migrating, Closing, and Deleting.
If the number of concurrent migration tasks exceeds the limit, scheduled tasks may not be executed as expected.
Bandwidth and QPS
Data Online Migration limits the maximum bandwidth and QPS (queries per second, or files migrated per second) for migration tasks. The following table lists the limits for each region.
Region | Maximum bandwidth per task | Maximum QPS per task |
China (Hangzhou) | 2Gbps | 2000 |
China (Shanghai) | 2Gbps | 2000 |
China (Beijing) | 2Gbps | 2000 |
China (Ulanqab) | 2Gbps | 2000 |
China (Shenzhen) | 2Gbps | 2000 |
China (Chengdu) | 2Gbps | 2000 |
China (Hong Kong) | 2Gbps | 2000 |
Japan (Tokyo) | 1Gbps | 2000 |
Singapore | 1Gbps | 2000 |
Germany (Frankfurt) | 1Gbps | 2000 |
US (Virginia) | 1Gbps | 2000 |
In addition to the preceding limits, if the destination data address type is LocalFs, the maximum QPS per task is 200.
The bandwidth and QPS configurations for migration tasks represent the maximum limits. The actual bandwidth and QPS depend on the read and write capabilities of the source and destination.
Data Online Migration consumes resources at both the source and destination addresses, which may affect your business operations. If your business is important, evaluate the impact in advance and set throttling for migration tasks or start migration tasks during off-peak hours.
If you need more public bandwidth, purchase ECS instances and public bandwidth, and migrate through an agent. Make sure to select the VPC network type for the agent. For more information, see Migrate data by using agents.
Other limits
Limitations | Description |
Migration result verification | After a data migration task is complete, you must check whether the data at the destination data address is consistent with the data at the source data address. Warning Make sure that you verify the migrated data at the destination after the migration task is complete. If you delete the data at the source data address before you verify the migrated data at the destination data address, you are liable for the losses and consequences caused by any data loss. |
Archive data files | For archived data, you must restore the data before you create a migration task. When you restore data, take note of the following items:
Note Data Online Migration does not restore data at the source. If files at the source are not restored or are being restored, these files fail to be migrated. |
Cross-border migration | Cross-border migration over the Internet may fail due to network instability. |