Persistence Overview

In-memory with optional durability

Redis is fast because data lives in memory. Persistence writes to disk so a restart can reload state.

RDB snapshots

Point-in-time dumps (RDB) are compact and good for backups. You can lose recent writes since the last snapshot.

AOF log

Append-only file (AOF) records write commands for better durability at some cost in disk and replay time.

Practical takeaway

• Treat cache data as disposable unless configured otherwise
• For sessions or queues, learn your host's persistence settings
• Backups and replicas matter before production
• Read Redis docs before changing save or appendonly