CompTIA Server+ (SK0-005)Security and Disaster RecoveryHard
A system administrator is setting up a highly available database cluster. The requirement is for the database to remain continuously accessible even if one of the database servers fails, with no data loss and minimal impact on application performance. Which type of database replication would best meet these demanding requirements?
- ATransactional replication
- BSynchronous replication
- CSnapshot replication
- DAsynchronous replication
Show answer & explanationAnswer & explanation
Correct answer: B. Synchronous replication
Synchronous replication ensures that a transaction is committed to both the primary and secondary database servers before it is considered complete. This guarantees 'no data loss' (zero RPO) and continuous consistency, making it ideal for 'highly available' and 'continuously accessible' systems, even though it can introduce some latency ('minimal impact on application performance').
Why the other options are wrong
- A. Transactional replication typically applies to specific transactions or changes, not necessarily full database failover with zero data loss for high availability.
- C. Snapshot replication copies the database at a specific point in time, not suitable for continuous availability with no data loss.
- D. Asynchronous replication commits data to the primary first, then replicates. This has a risk of data loss on primary failure.
Synchronous Replication
A data replication method where data is written to both the primary and secondary storage/database systems simultaneously before a write operation is acknowledged as complete.
- Guarantees zero data loss (RPO = 0).
- Provides immediate data consistency between replicas.
- Introduces latency, as the primary must wait for acknowledgment from the secondary.
Memory trick: Replication Sync: 'Sync' up now, or 'Async' later?