This topic describes how to use Data Transmission Service (DTS) to migrate data from standalone user-created MongoDB databases to Alibaba Cloud. DTS supports full data migration and incremental data migration.

To migrate all data without service interruption, you can select both full data migration and incremental data migration. You can also use the built-in commands of MongoDB to migrate user-created MongoDB databases. For more information, see Migrate user-created databases to Alibaba Cloud by using tools provided by MongoDB.

For more information about data migration or synchronization solutions, see Overview.

Prerequisites

  • The version of the user-created MongoDB database is 3.0, 3.2, or 3.4.
  • The storage space of the ApsaraDB for MongoDB instance is larger than the size of the user-created MongoDB database.

Precautions

  • To avoid service disruptions, we recommend that you migrate data during off-peak hours.
  • If the source user-created MongoDB database and the destination ApsaraDB for MongoDB instance run different MongoDB versions or storage engines, ensure that your applications can run on both databases. For more information about MongoDB versions and storage engines that are supported by ApsaraDB for MongoDB, see MongoDB versions and storage engines.
  • To migrate incremental data from a standalone user-created MongoDB database, you must enable the oplog feature for the database. For more information, see Preparations for incremental data migration.

Billing

Migration type Instance configurations Internet traffic
Full data migration Free of charge. Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Pricing.
Incremental data migration Charged. For more information, see Pricing.

Migration types

  • Full data migration: All historical data in the source MongoDB database is migrated to the destination MongoDB database.
    Note Data migration is supported at the database, collection, and index levels.
  • Incremental data migration: After full data migration, incremental data is synchronized to the destination MongoDB database.
    Note
    • The create and delete operations for databases, collections, and indexes can be synchronized.
    • The create, delete, and update operations for documents can also be synchronized.

Permissions required for database accounts

Database Full data migration Incremental data migration
Source user-created MongoDB database Read permissions on the source database Read permissions on the source database, admin database, and local database
Destination ApsaraDB for MongoDB instance Read/write permissions on the destination database Read/write permissions on the destination database

For more information about how to create and authorize a database account:

Preparations for incremental data migration

Before you use DTS to migrate incremental data, enable the oplog feature for the source database. If you only perform full data migration, skip the following steps.

Note This operation restarts the MongoDB database. We recommend that you perform this operation during off-peak hours.
  1. Use Mongo Shell to connect to the user-created MongoDB database.
  2. Run the following commands to shut down the MongoDB database:
    use admin
    db.shutdownServer()
  3. Run the following command to start the MongoDB database in the background as a replica set:
    mongod --port 27017 --dbpath /var/lib/mongodb --logpath /var/log/mongodb/mongod.log --replSet rs0 --bind_ip 0.0.0.0 --auth --fork
    Note
    • In this command, /var/lib/mongodb is the database path, and /var/log/mongodb/mongod.log is the log file path. Specify the paths based on business needs.
    • This command uses 0.0.0.0 as the associated IP address of the MongoDB database. This allows you to access the database by using all IP addresses. After the migration is complete, run the kill command to end the process, and start the MongoDB database by using the original configuration file.
    • This command enables authentication. You can only access the database after you pass the authentication.
  4. Use Mongo Shell to reconnect to the user-created MongoDB database.
  5. Run the following commands to initialize the replica set:
    use admin
    rs.initiate()
  6. The role of the current node changes to primary.
    Note You can run the rs.printReplicationInfo() command to view the status of oplog.

Procedure

  1. Log on to the DTS console.
  2. In the left-side navigation pane, click Data Migration.
  3. In the Migration Tasks section, select the region in which the ApsaraDB for MongoDB instance resides.
    Select a region
  4. In the upper-right corner, click Create Migration Task.
  5. Configure the source and destination databases.
    Configure the source and destination databases
    Section Parameter Description
    N/A Task name DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
    Source Database Instance Type Select an instance type based on the location where the database is deployed. In this topic, a User-Created Database with Public IP Address is used as an example.
    Note If you select other instance types, you must prepare the environments that are required for the source database. For more information, see Preparation overview.
    Instance Region If Instance Type is set to User-Created Database with Public IP Address, you do not need to specify the Instance Region parameter.
    Note If you have configured a whitelist for the user-created MongoDB database, you must add the CIDR blocks of DTS servers to the whitelist. You can click Get IP Address Segment of DTS next to Instance Region to obtain the CIDR blocks of DTS servers.
    Database Type Select MongoDB.
    Hostname or IP Address Enter the endpoint that is used to connect to the user-created MongoDB database. In this example, enter the public IP address.
    Port Number Enter the service port of the user-created MongoDB database.
    Note In this example, the service port of the user-created MongoDB database must be open to the public network.
    Database Name Enter the name of the authentication database to which the database account belongs.
    Database Account Enter the username of the database account that you use to manage the source database. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password Enter the password of the database account.
    Note After you specify the source database information, click Test Connectivity next to Database Password to check whether the information is correct. If the information is correct, the Passed message is displayed. If the Failed message is displayed, you can click Check next to the Failed message to modify the information as prompted.
    Connection Method Select Non-encrypted.
    Note The SSL-encrypted option is available only when you migrate MongoDB Atlas.
    Destination Database Instance Type Select MongoDB Instance.
    Instance Region Select the region in which the destination ApsaraDB for MongoDB instance resides.
    MongoDB Instance ID Select the ID of the destination ApsaraDB for MongoDB instance.
    Database Name Enter the name of the authentication database to which the database account belongs.
    Note If you want to use the root account, specify admin for the Database Name parameter.
    Database Account Enter the username of the database account that you use to manage the destination database. For more information about the permissions that are required for the account, see Permissions required for database accounts.
    Database Password Enter the password of the database account.
    Note After you specify the destination database information, click Test Connectivity next to Database Password to check whether the information is correct. If the information is correct, the Passed message is displayed. If the Failed message is displayed, click Check next to the Failed message to modify the information as prompted.
  6. In the lower-right corner of the page, click Set Whitelist and Next.
    Note The CIDR blocks of DTS servers are automatically added to the whitelist of the destination RDS instance. This ensures that DTS servers can connect to the destination ApsaraDB for MongoDB instance. After the migration is completed, you can remove these CIDR blocks from the whitelist. For more information, see Configure a whitelist for a replica set instance.
  7. Configure migration types and objects to be migrated.
    Select the migration types and objects to be migrated
    Parameter Description
    Migration Types
    • To perform only full data migration, select Full Data Migration.
    • To migrate data with minimal downtime, select both Full Data Migration and Incremental Data Migration.
      Note
      • Before migrating incremental data from a standalone user-created MongoDB database, you must enable oplog for the database. For more information, see Preparations for incremental data migration.
      • If the Incremental Data Migration option is not selected, do not write new data to the user-created MongoDB database when full data migration is in progress. Otherwise, data inconsistency may occur.
    Migration objects
    • Select objects from the Available section and click the Right arrow icon to move the objects to the Selected section.
      Note
      • Data in the admin and local databases cannot be migrated.
      • The config database is an internal database. We recommend that you do not migrate data in the config database.
    • A migration object can be a database, collection, or function.
    • By default, the name of an object remains unchanged after migration. You can change the names of the objects in the destination RDS instance by using the object name mapping feature. For more information, see Object name mapping.
  8. In the lower-right corner of the page, click Precheck.
    Note
    • Before you can start the data migration task, a precheck is performed. You can start the data migration task only after the task passes the precheck.
    • If the task fails to pass the precheck, click the Info icon icon next to each failed item to view details. Troubleshoot the issues based on the causes and run the precheck again.
  9. After the task passes the precheck, click Next.
  10. In the Confirm Settings dialog box, specify the Channel Specification parameter and select Data Transmission Service (Pay-As-You-Go) Service Terms.
  11. Click Buy and Start to start the migration task.
    • Full data migration

      Do not manually stop a task during full data migration. Otherwise, the system may fail to perform a full data migration. Wait until the data migration task automatically stops.

    • Incremental data migration

      An incremental data migration task does not automatically stop. You must manually stop the migration task.

      Note Select an appropriate time to manually stop the migration task. For example, you can stop the migration task during off-peak hours or before you switch your workloads to the destination instance.
      1. Wait until Incremental Data Migration and The migration task is not delayed appear in the progress bar of the migration task. Then, stop writing data to the source database for a few minutes. The delay time of incremental data migration may be displayed in the progress bar.
      2. After the status of Incremental Data Migration changes to The migration task is not delayed, stop the migration task.No delay exists during incremental data migration
  12. Switch your workloads to the ApsaraDB for MongoDB instance.