Setting up asynchronous primary-replica replication in MySQL
Jul 06, 2025 am 02:52 AMTo set up asynchronous master-slave replication for MySQL, follow these steps: 1. Prepare the master server, enable binary logs and set a unique server-id, create a replication user and record the current log location; 2. Use mysqldump to back up the master library data and import it to the slave server; 3. Configure the server-id and relay-log of the slave server, use the CHANGE MASTER command to connect to the master library and start the replication thread; 4. Check for common problems, such as network, permissions, data consistency and self-increase conflicts, and monitor replication delays. Follow the steps above to ensure that the configuration is completed correctly.
Setting up asynchronous primary-replica replication in MySQL is a common way to offload read traffic, provide redundancy, and help with backups. It's not overly complicated, but there are several important steps you need to follow carefully.

1. Prepare the Primary Server
Before setting up replication, make sure your primary server is configured correctly. You'll need to enable binary logging and assign a unique server ID.

- Edit your MySQL configuration file (usually
my.cnf
ormy.ini
) and add these lines under the[mysqld]
section:
server-id=1 log-bin=mysql-bin
- Restart MySQL to apply the changes.
- Create a dedicated replication user on the primary:
CREATE USER 'replica_user'@'%' IDENTIFIED BY 'your_password'; GRANT REPLICATION SLAVE ON *.* TO 'replica_user'@'%'; FLUSH PRIVILEGES;
This user will be used by the replica to connect and read binary logs from the primary.
Now check the current binary log position on the primary:

SHOW MASTER STATUS;
Take note of the File
and Position
values ??— you'll need them later when configuring the replica.
2. Take a Backup of the Primary Data
To get the replica in sync, you need a consistent snapshot of the primary data. The easiest way is to use mysqldump
.
Run this command on the primary:
mysqldump --all-databases --master-data=2 --single-transaction -u root -p > backup.sql
-
--master-data=2
adds the binary log position as a comment in the dump file. -
--single-transaction
ensures a consistent view of the database without locking tables for long.
Transfer the backup file to the replica server using scp
, rsync
, or any method you prefer.
Then import it into the replica:
mysql -u root -p < backup.sql
3. Configure the Replica Server
On the replica, edit its MySQL config and set a different server ID (it must be unique across the replication topology):
server-id=2
Also, if you want the replica to keep a record of the replicated events, you can enable relay logs:
relay-log=mysql-relay-bin
Restart MySQL after making changes.
Now, configure the replica to connect to the primary using the credentials and log position you recorded earlier:
CHANGE MASTER TO MASTER_HOST='primary_server_ip', MASTER_USER='replica_user', MASTER_PASSWORD='your_password', MASTER_LOG_FILE='recorded_log_file_name', MASTER_LOG_POS=recorded_position;
Once that's done, start the replication threads:
START SLAVE;
You can check the status with:
SHOW SLAVE STATUS\G
Look for Slave_IO_Running: Yes
and Slave_SQL_Running: Yes
. If both are yes and there are no errors, replication is working.
4. Common Issues and Tips
Replication settings can fail for various reasons. Here are some common issues and how to avoid them:
- Network connectivity : Make sure the replica can reach the primary on port 3306.
- Firewall rules : Double-check that the firewall allows traffic between the servers.
- User permissions : Confirm that the replication user has the correct privileges.
- Data inconsistency : If the replica's data doesn't match the primary, replication might break. Use tools like
pt-table-checksum
to verify consistency. - Auto-increment conflicts : If you ever switch to multi-source or circular replication, consider adjusting
auto_increment_offset
andauto_increment_increment
.
Also, don't forget to monitor replication lag. You can see it via SHOW SLAVE STATUS
— look at the Seconds_Behind_Master
field.
That's basically how you set up asynchronous replication in MySQL. It's straightforward once you've done it a few times, but always double-check each step — especially the server IDs and log positions.
The above is the detailed content of Setting up asynchronous primary-replica replication in MySQL. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

1. The first choice for the Laravel MySQL Vue/React combination in the PHP development question and answer community is the first choice for Laravel MySQL Vue/React combination, due to its maturity in the ecosystem and high development efficiency; 2. High performance requires dependence on cache (Redis), database optimization, CDN and asynchronous queues; 3. Security must be done with input filtering, CSRF protection, HTTPS, password encryption and permission control; 4. Money optional advertising, member subscription, rewards, commissions, knowledge payment and other models, the core is to match community tone and user needs.

There are three main ways to set environment variables in PHP: 1. Global configuration through php.ini; 2. Passed through a web server (such as SetEnv of Apache or fastcgi_param of Nginx); 3. Use putenv() function in PHP scripts. Among them, php.ini is suitable for global and infrequently changing configurations, web server configuration is suitable for scenarios that need to be isolated, and putenv() is suitable for temporary variables. Persistence policies include configuration files (such as php.ini or web server configuration), .env files are loaded with dotenv library, and dynamic injection of variables in CI/CD processes. Security management sensitive information should be avoided hard-coded, and it is recommended to use.en

To achieve MySQL deployment automation, the key is to use Terraform to define resources, Ansible management configuration, Git for version control, and strengthen security and permission management. 1. Use Terraform to define MySQL instances, such as the version, type, access control and other resource attributes of AWSRDS; 2. Use AnsiblePlaybook to realize detailed configurations such as database user creation, permission settings, etc.; 3. All configuration files are included in Git management, support change tracking and collaborative development; 4. Avoid hard-coded sensitive information, use Vault or AnsibleVault to manage passwords, and set access control and minimum permission principles.

To collect user behavior data, you need to record browsing, search, purchase and other information into the database through PHP, and clean and analyze it to explore interest preferences; 2. The selection of recommendation algorithms should be determined based on data characteristics: based on content, collaborative filtering, rules or mixed recommendations; 3. Collaborative filtering can be implemented in PHP to calculate user cosine similarity, select K nearest neighbors, weighted prediction scores and recommend high-scoring products; 4. Performance evaluation uses accuracy, recall, F1 value and CTR, conversion rate and verify the effect through A/B tests; 5. Cold start problems can be alleviated through product attributes, user registration information, popular recommendations and expert evaluations; 6. Performance optimization methods include cached recommendation results, asynchronous processing, distributed computing and SQL query optimization, thereby improving recommendation efficiency and user experience.

Why do I need SSL/TLS encryption MySQL connection? Because unencrypted connections may cause sensitive data to be intercepted, enabling SSL/TLS can prevent man-in-the-middle attacks and meet compliance requirements; 2. How to configure SSL/TLS for MySQL? You need to generate a certificate and a private key, modify the configuration file to specify the ssl-ca, ssl-cert and ssl-key paths and restart the service; 3. How to force SSL when the client connects? Implemented by specifying REQUIRESSL or REQUIREX509 when creating a user; 4. Details that are easily overlooked in SSL configuration include certificate path permissions, certificate expiration issues, and client configuration requirements.

When choosing a suitable PHP framework, you need to consider comprehensively according to project needs: Laravel is suitable for rapid development and provides EloquentORM and Blade template engines, which are convenient for database operation and dynamic form rendering; Symfony is more flexible and suitable for complex systems; CodeIgniter is lightweight and suitable for simple applications with high performance requirements. 2. To ensure the accuracy of AI models, we need to start with high-quality data training, reasonable selection of evaluation indicators (such as accuracy, recall, F1 value), regular performance evaluation and model tuning, and ensure code quality through unit testing and integration testing, while continuously monitoring the input data to prevent data drift. 3. Many measures are required to protect user privacy: encrypt and store sensitive data (such as AES

PHP plays the role of connector and brain center in intelligent customer service, responsible for connecting front-end input, database storage and external AI services; 2. When implementing it, it is necessary to build a multi-layer architecture: the front-end receives user messages, the PHP back-end preprocesses and routes requests, first matches the local knowledge base, and misses, call external AI services such as OpenAI or Dialogflow to obtain intelligent reply; 3. Session management is written to MySQL and other databases by PHP to ensure context continuity; 4. Integrated AI services need to use Guzzle to send HTTP requests, safely store APIKeys, and do a good job of error handling and response analysis; 5. Database design must include sessions, messages, knowledge bases, and user tables, reasonably build indexes, ensure security and performance, and support robot memory

To enable PHP containers to support automatic construction, the core lies in configuring the continuous integration (CI) process. 1. Use Dockerfile to define the PHP environment, including basic image, extension installation, dependency management and permission settings; 2. Configure CI/CD tools such as GitLabCI, and define the build, test and deployment stages through the .gitlab-ci.yml file to achieve automatic construction, testing and deployment; 3. Integrate test frameworks such as PHPUnit to ensure that tests are automatically run after code changes; 4. Use automated deployment strategies such as Kubernetes to define deployment configuration through the deployment.yaml file; 5. Optimize Dockerfile and adopt multi-stage construction
