Overview
Infrequently requested files can be evicted from edge caches. A planned content-copy layer between the origin and the edge can give cold requests a more suitable place to read from.
This page describes an architecture to evaluate. Durable copies, retention periods and regional placement depend on the actual storage and delivery configuration; permanent caching or a perfect hit rate is not promised.
Separate source files, copies and edge caches
The source establishes the authoritative content, a copy layer provides repeatable reads, and edge caching serves nearby visitors. Their retention, update and failure policies serve different purposes.
Source files
Keep recoverable master versions and integrity information as the basis for publishing and disaster recovery.
Content copies
Place copies according to audience location, storage cost and cold-request load. Define the fallback when a copy cannot be read.
Edge caching
Handle repeated requests while observing cache keys, freshness and invalidation policies.
Design the entire content lifecycle
Copying a file does not make updates propagate correctly by itself. Version identifiers, deletion order and permission changes need to cover every layer.
- Publish versioned assets at new addresses and retain an appropriate transition window for old versions.
- When a stable address changes, verify consistency between copies and edge caches.
- When withdrawing restricted content, check the source, copies, caches and external links.
Evaluate benefits using actual usage
Fewer origin reads can introduce storage, replication and management costs. Compare all costs over the same period before deciding whether the architecture fits.
| Observation | Record | Decision supported |
|---|---|---|
| Cold requests | First-read share, object size and visitor region | Whether another copy layer is useful |
| Content updates | Update frequency, retained versions and invalidation time | Version and cleanup policy |
| Origin load | Origin bytes, concurrency and errors | Origin protection and capacity planning |
| Total cost | Storage, replication, requests and transfer | Overall cost rather than isolated savings |
Implementation & checks
- 01
Choose representative assets
Start with packages, course videos or rarely changing media, including both popular and long-tail requests.
- 02
Verify the cold path
Test missing copies, origin timeouts, expired permissions and behavior after deletion.
- 03
Observe and adjust
Refine retention based on cache behavior, origin load and operational effort.