Operations are performed by Cache Reserve on behalf of the user to write data from the origin to Cache Reserve and to pass that data downstream to other parts of Cloudflare’s network. These operations are managed internally by Cloudflare.
Class A operations are performed based on cache misses from Cloudflare’s CDN. When a request cannot be served from cache, it will be fetched from the origin and written to cache reserve as well as our edge caches on the way back to the visitor.
Class B operations are performed when data needs to be fetched from Cache Reserve to respond to a miss in the edge cache.
Purge requests are free operations. Invalidation requests can result in Class A operations.
Purging content forces a cache miss in both Cache Reserve and the edge cache, regardless of purge type. The next request for that content is fetched from your origin and written to Cache Reserve again, which is a Class A operation.
Purging by URL deletes content from Cache Reserve. Purging by tag, hostname, prefix, or everything does not delete it right away. Matching content stays stored and continues to incur storage costs until a later request replaces it or its retention period ends.
Invalidating content keeps it in Cache Reserve and marks it for revalidation. If your origin responds with 304 Not Modified, Cloudflare reuses the stored content instead of fetching it from your origin. Updating the stored content after the 304 response is a Class A operation. Invalidating by URL also updates the stored content when you send the request, which is a Class A operation. Invalidated content remains stored and continues to incur storage costs.