Copying data to multiple servers

Day 122 of 149

👉 Full deep-dive with code examples

The Backup Copy Analogy

Important documents:

One copy at home

One copy at the bank

One copy at your lawyer's

If your house burns down, you still have copies!

Database Replication keeps copies of your database in multiple places!

Why Replicate?

Safety:

If one server fails, another replica may still have the data (and can take over, depending on your setup)

Can reduce data-loss risk, but replication is not a full backup strategy by itself

Speed:

Users far away can read from a nearby replica

Can reduce read latency for globally distributed users

Availability:

One server down → Others handle requests

Less downtime for users (depending on failover and client behavior)

Types of Replication

Primary-Replica:

Primary (writes) ──→ Replica 1 (reads) └──→ Replica 2 (reads)

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One leader accepts writes

Replicas get copies, handle reads

Multi-Primary:

Multiple servers…