CDN Caching and the Island Distance Problem

A content delivery network keeps copies of eligible files closer to visitors. That can improve the feel of a brochure, menu, or product catalog, while dynamic actions still need to reach an origin system. The important question is not whether a CDN is fashionable; it is which content can safely be served from a cache.

Separate public assets from private data. Images, stylesheets, and versioned scripts are usually good candidates. Account pages, inventory changes, and checkout states need a more careful policy. Use file versioning so a new design does not wait for an old copy to disappear.

Test cache behavior after publishing. Confirm that a customer sees the current hours, that a changed price does not linger in an old response, and that an origin outage has a clear fallback. The technical setup should serve the business promise, not surprise it.

Separate distance from freshness

A content delivery network can make a public page feel closer to a visitor, which is useful when a Hawaiʻi audience is reaching an origin hosted far away. It cannot make every request safe to cache. Begin by classifying responses: public images and versioned stylesheets, public editorial pages, personalized account data, inventory, and checkout state. The classification should follow the business risk of stale information, not the convenience of a vendor dashboard.

Diagnose the actual path

Inspect response headers, cache status, time to first byte, and content age from at least two networks. Test a page before and after a known edit, then purge or version the asset and repeat. Compare a static image, a category page, and a form endpoint. A faster first byte may still leave a heavy image or third-party script as the largest delay. Measure the whole task, not the green cache badge.

Design invalidation before launch

Use hashed or versioned filenames for styles and scripts, define a short policy for hours and prices, and document who can purge a cache. Keep private cookies and authenticated responses out of public caching. If a shop changes a delivery window because of weather, the update path must be obvious and fast enough for the business promise. Write the rollback instruction while the system is calm.

Local example with a real exception

A Maui food producer might serve a public catalog and a pickup calendar. Product photography and editorial stories can be cached for a long time, while the pickup calendar needs a shorter lifetime or a deliberate invalidation step. If the team caches the calendar like an image, a customer may arrive at the wrong time. If it caches nothing, the whole site pays the inter-island distance cost.

Metrics, not mythology

Track cache hit ratio by route, stale-response incidents, purge time, origin error rate, p75 and p95 response time, image bytes, and the completion of the primary task. A high hit ratio can hide a wrong cache key or a stale business fact. A low ratio may be acceptable for a personalized workflow. Compare results by island and network where the sample is large enough, and label small samples as directional.

Limits and source trail

Caching does not solve poor source content, bad DNS, a failing origin database, or a third-party payment outage. Avoid cache rules copied from a tutorial without reviewing cookies and headers. Use the Cloudflare caching documentation for product-specific behavior, then verify with raw responses from the site. Treat public broadband availability as context rather than proof of a visitor’s actual path.

Field note

Give every cache rule a business owner and a sentence describing the cost of staleness. If nobody can say who should purge a changed route, price, or closure notice, the rule is unfinished. A small table of routes, lifetimes, and invalidation actions is often more useful than a dashboard full of aggregate cache statistics.

Primary references: Cloudflare: Cache concepts · Hawaiʻi Broadband Office