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Describe the process of configuring MySQL Master-Slave Replication.

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Configuring MySQL Master-Slave Replication involves setting up a primary MySQL server (the master) and one or more secondary servers (the slaves) that replicate data from the master. Here's a detailed technical explanation of the process:

  1. Prerequisites:
    • Ensure that MySQL is installed on all servers (master and slaves).
    • Verify network connectivity between the master and slave servers.
    • Have administrative privileges to configure MySQL on all servers.
  2. Configure Master Server:
    • Edit the MySQL configuration file (typically my.cnf or my.ini), usually located in /etc/mysql/ or /etc/my.cnf on Linux systems.
    • Set server-id parameter uniquely for each server. For the master, set it to any positive integer (e.g., server-id = 1).
    • Enable binary logging by adding log-bin parameter in the configuration file. This is essential for replication.
    • Optionally, set other parameters like binlog_format (typically set to ROW for better replication performance) and binlog_do_db or binlog_ignore_db to specify databases to include or exclude from replication.
    • Restart the MySQL service for the changes to take effect.
  3. Create Replication User:
    • Log in to the MySQL server as an administrative user.
    • Create a user specifically for replication with appropriate privileges. For security, limit this user to only have replication-related permissions.
    • Grant REPLICATION SLAVE privilege to the user.
  4. Backup Master Data (Optional but Recommended):
    • If the master server already has data, consider taking a backup using tools like mysqldump or other backup solutions. This backup will be used to initialize the slave server(s).
  5. Configure Slave Server(s):
    • Edit the MySQL configuration file on each slave server.
    • Set server-id to a unique value (e.g., server-id = 2 for the first slave, server-id = 3 for the second, and so on).
    • Optionally, set other parameters like relay-log and relay-log-index to configure relay log files on the slave.
    • Restart the MySQL service.
  6. Start Replication Process:
    • On the slave server, connect to the MySQL instance.
    • Issue the CHANGE MASTER TO command to configure the replication settings. This includes specifying the master host, port, replication user credentials, and log file coordinates from the master binary log (MASTER_LOG_FILE and MASTER_LOG_POS).
    • Start the slave threads with START SLAVE.
  7. Verify Replication:
    • Check the replication status on the slave server using commands like SHOW SLAVE STATUS\G to ensure there are no errors.
    • Monitor the replication process regularly to detect any issues.
  8. Test Replication:
    • Perform tests such as creating, updating, and deleting data on the master server to ensure that changes are replicated to the slave server(s) correctly.
  9. Monitor and Maintain:
    • Continuously monitor the replication process for errors or delays.
    • Regularly backup and maintain the master and slave databases.
    • Update configuration or upgrade MySQL versions as needed, ensuring compatibility with replication settings.