What mechanism maintains coherency between the origin and FlexCache blocks?

• A. Invalidation messaging over inter-cluster links.
• B. Direct data synchronization every minute.
• C. Explicit manual cache invalidation by admins.
• D. SnapMirror asynchronous replication

Answer: (A)

Coherence between the origin and FlexCache blocks is maintained by invalidation messaging over inter-cluster links. When the origin updates data, it sends invalidation notices to the FlexCache blocks, marking the cached entries as stale so subsequent reads fetch fresh data from the origin or revalidate the cache. This approach avoids constant data syncing and ensures timely, correct data without heavy replication overhead. Manual invalidation is not practical at scale, and SnapMirror handles replication, not real-time cache coherence.