Design Resilient Architectures

Multiple subscribers are attached to one SNS topic, but each should receive only the messages relevant to it (for example, only high-priority orders). How can this be done without extra filtering code in the subscribers?

• AApply an SNS filter policy so each subscriber gets only matching messages.
• BCreate a separate topic for every possible message attribute combination.
• CHave each subscriber receive all messages and discard the irrelevant ones.
• DMove to a single SQS queue and let one consumer sort the messages.

SNS subscription filter policies match message attributes so each subscriber receives only relevant messages, with no subscriber-side filtering. A topic per combination explodes in count, receiving everything wastes work, and a single queue removes the fan-out.

An application uses an RDS Multi-AZ deployment, and the team believes it is protected against a full Regional outage. Which statement is accurate?

• AMulti-AZ replicates the database across multiple Regions automatically.
• BMulti-AZ requires no additional design for Regional disaster recovery.
• CMulti-AZ protects against an AZ failure but not a full Regional outage.
• DMulti-AZ and single-AZ offer identical protection against Regional outages.

Multi-AZ provides failover across Availability Zones within one Region; surviving a full Regional outage requires a separate multi-Region DR design. It does not replicate across Regions, and it is stronger than single-AZ for AZ failures.