Data Online Migration is free of charge. However, you are charged for data uploads, data downloads, and API requests. This topic describes how to calculate the fees that you are charged when you use Data Online Migration to migrate data.

Migration process

The online migration process includes the following steps:
  1. Retrieve the details of the data to be migrated: Data Online Migration compares the size, ContentType, LastModify, and other metadata information about each source file with files at the destination data address. Then, Data Online Migration determines whether to migrate or skip migrating the source file based on the file overwrite method that you specified for the current migration job.
  2. Migrate data: Data Online Migration migrates the data from the source data address to the destination data address.
  3. Check data integrity: Data Online Migration compares the migrated data with the source data to ensure data integrity.
  4. Generate migration logs: Data Online Migration generates migration logs and uploads the migration logs to the destination data address after you click Generate Migration Report.

Number of API requests

API requests are required when you compare files at the source and destination data addresses, migrate the data to the destination data address, and check data integrity. The number of API requests required varies based on the scenario. This section describes how to calculate the number of API requests required when a single file is migrated.
Notice
  • The following description applies only when the data source is a third-party cloud service or Object Storage Service (OSS). When you migrate data from Apsara File Storage NAS, HTTP or HTTPS endpoints, or Elastic Compute Service (ECS) instances, you are not charged for the API requests that are made to access these data sources.
  • The following rules for calculating the number of API requests apply only if your migration is successful.
  • The following API requests are made to migrate a file that has a unique name both at the source and destination data addresses:
    • Source side
      • A GetMeta request to compare data before data is migrated
      • A GetObject request to start migrating data
    • Destination side
      • A GetMeta request to compare data before data is migrated
      • A PutObject request to start migrating data
        Notice If the size of a file is greater than or equal to 150 MB, the file is split into multiple parts before it is uploaded. The part size is 50 MB and the last part can be smaller than 50 MB. The number of API requests required to upload the file is equal to the number of parts into which the file is split. For example, if you want to upload a file of 150 MB, three PutObject requests are required because the file is split into three parts.
      • A GetMeta request to check data integrity after data is migrated
  • The following API requests are made to migrate a file that is named the same as a file at the destination data address:
    • Source side
      • A GetMeta request to compare data before data is migrated
      • A GetObject request to start migrating data
    • Destination side
      • A GetMeta request to compare data before data is migrated
      • A PutObject request to start migrating data
        Notice If the size of a file is greater than or equal to 150 MB, the file is split into multiple parts before it is uploaded. The part size is 50 MB and the last part can be smaller than 50 MB. The number of API requests required to upload the file is equal to the number of parts into which the file is split. For example, if you want to upload a file of 150 MB, three PutObject requests are required because the file is split into three parts.
      • A GetMeta request to check data integrity after data is migrated
  • The following API requests are made to skip migrating a file that is named the same as a file at the destination data address:
    • Source side
      • A GetMeta request to compare data before data is migrated
    • Destination side
      • A GetMeta request to compare data before data is migrated
      • A GetMeta request to check data integrity after data is migrated
For example, you need to use a migration job to migrate 1,000 files. The size of each file is smaller than 150 MB. Among the 1,000 files, 500 files have a unique name both at the source and destination data addresses and need to be migrated. Among the other 500 files, 300 files need to be migrated and the other 200 files do not need to be migrated. If the migration job succeeds, use the following methods to calculate the total number of API requests sent to the source data address and the total number of API requests sent to the destination data address:
  • Source data address 
    500*2+300*2+200*1=1800
  • Destination data address 
    500*3+300*3+200*2=2800
Note For information about the fees for API requests, contact your cloud service provider. For information about the billable items and billing methods of OSS, see Overview.

Fees for traffic generated by data downloads and uploads

You are charged when data is downloaded from the source data address and uploaded to OSS. The fees for the traffic consumed to download and upload the data vary based on the scenario.
Notice
  • The following billing rules apply only for OSS and third-party cloud services. When you migrate data from Apsara File Storage NAS, HTTP or HTTPS endpoints, or ECS instances, you are not charged for downloading data.
  • The following rules apply only if your migration is successful.
  • Migrate data from a third-party cloud service

    You are charged for downloading data from the source data address. The consumed traffic depends on the amount of data that you want to download. You are charged by the cloud service provider that owns the source data address. You are not charged for the traffic consumed to upload data to OSS.

  • Migrate data from an OSS endpoint to another OSS endpoint within a region over an Alibaba Cloud internal network

    No fees are incurred because the data is downloaded or uploaded within the Alibaba Cloud internal network.

  • Migrate data from an OSS endpoint in one region to an OSS endpoint in another region over the Internet

    You are charged by OSS for downloading data from the source data address. The consumed traffic depends on the amount of data that you download. You are not charged for the traffic consumed to upload data to OSS.