Migrate a Cloud Databases instance from MariaDB or Percona to MySQL

  • Last updated on: 2019-01-14
  • Authored by: Kate Dougherty

This article shows you how to migrate a Cloud Databases instance from Percona® or MariaDB® back to a MySQL® solution. The steps assume that you haven’t enabled the root database user on the source or destination instance and that you’re using the Rackspace Cloud Control Panel to manage your Cloud Databases.

Because database replication isn’t available, this article includes some additional steps to ensure that no content is lost during the migration process. As a result, we recommend that you perform this upgrade during a low-traffic period.

Note: Before you upgrade from a Cloud Databases MariaDB or Percona instance to a MySQL database instance, identify any unique features of the prior datastore that you might be using and verify that the destination datastore also has them. You can add those unique features by creating links to the upstream content.

Back up the original Cloud Databases instance

It’s important to back up the original instance first. If you discover any structure discrepancies after you begin using the new MySQL instance, you can use the backup copy to rebuild your database in its previous MariaDB or Percona state.

Use the following steps to create a copy of the original instance:

  1. Log in to the Cloud Control Panel.

  2. In the top navigation bar, click Select a Product > Rackspace Cloud.

  3. Click Databases > MySQL.

    A list of your Cloud Databases instances appears.

  4. Click the gear icon for the instance that you want to back up, then select Create Backup.

  5. Enter a Name and Description for the backup, then click Create Backup.

Create the destination MySQL instance

Use the following steps to create a new Cloud Databases instance:

  1. In the Cloud Control Panel, click Databases > MySQL Instance.
  2. In the Identity section of the Create Instance page, enter an Instance Name and select a Region from the drop-down list.
  3. In the Engine section, choose the MySQL instance type that you want to use.
  4. In the Build section, select the amount of memory that you want the server to use from the RAM drop-down list and choose a Disk size.
  5. Click Create Single Instance.

Note: If your current database uses any custom my.cnf configuration options, review the configuration of the new instance to ensure that those options are updated before you import your database. This step is especially important when your configuration options involve character set and collation specifications. Custom my.cnf options can cause the imported content to populate the new database instance in an unexpected way, leading to discrepancies with table character data encoding.

Rebuild databases and users for a new MySQL instance

This section explains how to generate lists of databases and users from a MariaDB or Percona instance and recreate them on a MySQL 5.7 instance.

Rebuild databases on the MySQL 5.7 instance

Use the following steps to rebuild databases on the MySQL 5.7 instance:

  1. In the Cloud Control Panel, click on the MariaDB or Percona instance.

    The list of databases displays on the Instance Details page.

  2. Open the Instance Details page for the new MySQL 5.7 instance, click Create Database, and enter the name of a database from the MariaDB or Percona instance. Repeat this step until you have recreated all of the databases.

Rebuild users on the MySQL 5.7 instance

To rebuild users on the MySQL 5.7 instance, you first have to reconfigure the passwords for the database users. If your application is already configured for a specific password, you should have the list of passwords before you create the users so that you don’t have to update the application configuration later.

Use the following steps to rebuild users on the MySQL 5.7 instance:

  1. In the Cloud Control Panel, click on the MariaDB or Percona instance.

    The list of users displays on the Instance Details page.

  2. Open the Instance Details page for the new MySQL 5.7 instance, click Create User, and enter the name of a user from the MariaDB or Percona instance. Repeat this step until you have recreated all of the users.

Configure the application for read-only or maintenance mode

Configure your application or website to a maintenance mode or read-only state until the transfer is complete. This step prevents any new data from being added to the MariaDB or Percona instance while you’re finishing the upgrade and transitioning to the new MySQL 5.7 instance.

Note: The following sections describe how to export your current databases and import them to the new instance. During this process, the MariaDB or Percona database is in a read-only state, and any updates to the database could potentially be lost to the new destination instance during the export and import process.

Export databases from MariaDB or Percona and import them into MySQL 5.7

This section describes two methods for exporting and importing the databases by using the mysqldump command. This command locks the source database instance as it exports the data. Before you begin, ensure that your application is prepared for the database to be in a read-only state.

Export the list of databases and direct the output to the database instance

The following steps export a list of databases from your source instance and redirect the output to the destination instance that you choose.

Note: To complete the following steps, both instances must have a user who has full access to all of the databases that you want to export and import.

Use the following steps to export the list of databases and direct the output to the database instance:

  1. Log in to a cloud server that’s available within the same data center as your source and destination database instances.

  2. Run the mysqldump command, replacing the following items in each section of the command:

    • source\_db_user: The database that the user created on the source instance for the export
    • source_password: The password specified for the source database user
    • xxxxx.rackspaceclouddb.com: The host name of the source instance
    • database 01 database 02 database 03: A list of the databases that you’re exporting and importing
  3. Run the mysqldump command, replacing the following items in each section of the command:

    • destination_db_user: The database that the user created on the destination for the import
    • destination_password: The password specified for the destination database user
    • yyyyy.rackspaceclouddb.com: The host name of the destination instance

    The following code provides an example:

    mysqldump --user=source_db_user --host=xxxxx.rackspaceclouddb.com --password=source_password --no-create-db --databases database_01 database_02 database_03 | mysql   --user=destination_db_user --host=yyyyy.rackspaceclouddb.com --password=destination_password
    

Export the list of databases to a file on the server before importing

This method follows the same concept as the preceding method, but instead of redirecting the mysqldump export directly to the new instance, you first create a copy of the data and compress it on a disk. Then you import the content from this file to the destination instance.

Use the following steps to perform this task:

  1. Log in to a cloud server that is available within the same data center as your source and destination database instances.

  2. Run the mysqldump command, replacing the following items in each section of the command:

    • source\_db_user: The database that the user created on the source instance for the export
    • source_password: The password specified for the source database user
    • xxxxx.rackspaceclouddb.com: The host name of the source instance
    • database 01 database 02 database 03: A list of the databases that you’re exporting and importing

    The following code provides an example:

    mysqldump --user=source_db_user --host=xxxxx.rackspaceclouddb.com --password=source_password --no-create-db --databases database_01 database_02 database_03 |
    gzip
    -1 > sourceDB.sql.gz
    
  3. Run the mysql command, replacing the following items in each section of the command:

    • destination_db_user: The database that the user created on the destination for the import
    • destination_password: The password specified for the destination database user
    • yyyyy.rackspaceclouddb.com: The host name of the destination instance

    The following code provides an example:

     zcat sourceDB.sql.gz | mysql --user=destination_db_user --host=yyyyy.rackspaceclouddb.com --password=destination_password
    

Verify the dataset on the MySQL 5.7 instance

Before you transition to the new MySQL 5.7 instance, check the database content to verify that your data was imported and formatted in the way that you expected. The mysqldump export creates a logical copy of your database content. The destination MySQL 5.7 database instance uses this logical copy of your data to rebuild the database table files, using the updated file format that MySQL 5.7 implements. For this reason, it’s important to verify that certain configurations such as character sets and time zone data are updated to match your previous MariaDB or Percona database instance.

Note: We recommend that you use a staging or test server for your applications to verify functionality before you transition the applications to the new MySQL 5.7 instance.

Transition applications to the MySQL 5.7 instance

When you have imported and verified your data, you can transition your applications to the new database instance by using the new host name.

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