Three Main Data Replication Strategies

[armingli]

Replication is like backup, but owning a more important role than backup in distribute system.1

The Need for Replication

• Improving Availability
• Preparing for Disaster Recovery
• Enhancing Perfomance
• Geographical Considerations(eg.CDN)

Synchronous Replication

The primary node waits for all replica to finish the operation and get "All is well", then the process is complete.

Pros and Cons

• Fault Tolerance
• Potential Blocking Issues

Asynchronous Replication

Immediate Response to Client.

Pros and Cons

• Maximizing Throughput
• Possibility of Data Loss

Semi-synchronous Replication

It is a mix of the other two methods. It makes sure some of the updates are safe. It's a balanced approach.

• Synchronous Replication to Subset of Replicas
• Asynchronous Replication to Others

Pros and Cons

• Addressing Durability.
• Marginal Impact on Throughput.

Which one is right for you?

The factors we should Consider when you make decision.

• Criticality of Data
• Consistency Requirements
• System Throughput