A municipality must keep irreplaceable ordinance PDFs durable and available even if an entire AWS Region becomes unavailable. Which storage reliability strategy best fits?
Select an answer to reveal the explanation.
Short Explanation
One Region’s S3 durability is great until that Region is the problem. Cross-Region Replication puts a second, distant copy of those ordinance PDFs where a regional outage can’t erase them.
Full Explanation
Inspectors in the field need low-latency access to frequently read reference data that cannot tolerate repeated round trips to a regional database on every screen. Placing a cache tier such as ElastiCache (Redis/Memcached) or an application cache in front of the database for hot keys reduces latency while the database of record remains authoritative. Hitting the primary RDS instance synchronously for every identical lookup maximizes latency and load. Replicating the entire database to each inspector phone as the sole strategy creates sync and security problems. Turning off indexes and caching simultaneously worsens field performance. Exam caveat: caches need TTLs and invalidation aligned to how often code tables change; stale permit fee schedules can cause billing errors. Operational check: measure p95 lookup latency before and after cache introduction, force an invalidation after a reference update, and confirm inspectors see fresh values within policy. In municipal cloud governance, record the owners, success metrics, and rollback or restore contacts beside this technical choice so the next incident, budget review, or audit does not rediscover the decision from scratch under time pressure.