Asynchronous Replication:?

• Data is written to the primary database, and changes are replicated to

secondary databases after a delay.

• Advantages: Better performance due to less replication overhead.
• Disadvantages: Potential for data loss or inconsistency in the event of a

failure.

Tools for Replication:

• SQL Server: Use Always On Availability Groups or Transactional Replication.
• PostgreSQL: Use Streaming Replication or Logical Replication.
• MySQL: Use MySQL Replication or Group Replication.
• MongoDB: Use Replica Sets for automatic failover and high availability.

Example (PostgreSQL Streaming Replication):

# On Master Node

wal_level = replica

archive_mode = on

archive_command = 'cp %p /var/lib/postgresql/archive/%f'

# On Standby Node

primary_conninfo = 'host=master_ip port=5432 user=replication_user

password=replication_password'

Database Scaling & Performance