This topic describes the limits and performance metrics for Data Online Migration.
Resource count
Data Online Migration limits the number of resources, such as migration tasks, data addresses, agents, and channels.
Resource | Maximum number per region |
Migration task | 500 |
Data address | 1,000 |
Agent | 100 |
Channel | 100 |
Concurrent migration tasks
Data Online Migration limits the number of concurrent tasks. If you exceed the limit, new tasks fail to start. The limits for each region are listed below.
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 |
A migration task is considered running when its status is Starting, Preparing, Migrating, Stopping, or Deleting.
If the number of concurrent migration tasks exceeds the limit, scheduled tasks may not run as expected.
Task bandwidth and QPS
Data Online Migration limits the maximum bandwidth and queries per second (QPS) for each migration task. QPS refers to the number of files migrated per second. The limits for each region are listed below.
Region | Maximum bandwidth per task | Maximum QPS per task |
China (Hangzhou) | 2 Gbps | 2,000 |
China (Shanghai) | 2 Gbps | 2,000 |
China (Beijing) | 2 Gbps | 2,000 |
China (Ulanqab) | 2 Gbps | 2,000 |
China (Shenzhen) | 2 Gbps | 2,000 |
China (Chengdu) | 2 Gbps | 2,000 |
China (Hong Kong) | 2 Gbps | 2,000 |
Japan (Tokyo) | 1 Gbps | 2,000 |
Singapore | 1 Gbps | 2,000 |
Germany (Frankfurt) | 1 Gbps | 2,000 |
US (Virginia) | 1 Gbps | 2,000 |
In addition to the limits above, if the destination data address type is LocalFs, the maximum QPS for each task is 200.
The configured bandwidth and QPS for a migration task represent the maximum achievable values. The actual bandwidth and QPS depend on the read and write capabilities of the source and destination.
Data Online Migration consumes resources from both the source and destination, which might affect your business operations. If your business is critical, assess the impact and set a rate limit for the migration task, or run the task during off-peak hours.
If you need more public bandwidth, purchase Elastic Compute Service (ECS) instances and public bandwidth, and then migrate data using an agent. Set the agent network type to VPC. For more information, see Migrate data using an agent.
Channel bandwidth and QPS
Data Online Migration limits the bandwidth and QPS of channels. For scenarios that use an agent, Data Online Migration limits the channel bandwidth and QPS (requests per second, as migrating a single file requires multiple requests) at the UID level. If you need higher channel bandwidth and QPS, submit a ticket to request an increase.
Region | Maximum channel bandwidth per UID | Maximum channel QPS per UID |
Any region | 8 Gbps | 10,000 |
For example, if a user creates three channels in the China (Hangzhou) region, and these channels are associated with multiple tasks that run at the same time, the total traffic and QPS of these tasks are subject to the limits in the table above.
Other
Limitations | Description |
Migration result verification | After a migration task is complete, verify the data consistency between the source and destination. Warning After a migration task is complete, verify the migrated data at the destination. You are responsible for any loss or consequences that result from data loss caused by deleting the source data before you verify the destination data. |
Archived data | For archived data, you must restore it before you create a migration task. Note the following when you restore data:
Note Data Online Migration does not restore data from the source. If your source contains files that are not restored or are in the process of being restored, the migration of these files will fail. |
Cross-border migration | Cross-border migration over the public network may fail due to network instability. |