Multi-CDN setups still generate origin fill on cache misses — each CDN’s edge transfer and origin-pull path can meter differently. Estimate fill ≈ client_GB × (1−CHR) per CDN lane; keep $/GB Unknown until verified. Use Mode C.
Updated
Two CDN logos in front of one origin still share miss-driven fill — map edge vs origin meters per provider before blending.
Multi-CDN is an availability and bargaining pattern — not a single meter. PipeToll models each lane’s origin fill with CHR before comparing logos. See also CloudFront vs Cloudflare (already shipped) and multi-CDN.
Path templates to model
Active-active split — 50/50 clients; two cold caches can double origin pull versus one warm CDN.
Failover-only secondary — secondary CHR near zero during drills; budget drill fill.
Shielded origin — mid-tier reduces origin GB but adds another hop to price.
Object storage origin — miss fill may bill as S3 DT-out or private path; keep Unknown until cited.
Bypass / signed direct — large clients skipping CDN push 100% to origin egress.
Common traps
One blended “CDN $/GB.” Ignoring duplicate fill when both CDNs miss the same surge. Assuming multi-CDN always lowers origin cost. Skipping Mode C per lane. No savings guarantee from adding a second logo.
FinOps checklist
Export client GB and CHR (or miss ratio) per CDN lane.
Estimate fill ≈ client_GB × (1−CHR) per lane; sum carefully for shared origins.
Price edge and origin with dated cites; badge Unknown otherwise.
Document drill/failover months separately — literacy over scorecrowns. See methodology.
FinOps-liteUnknown until verified
Worked example (educational): 10 TB clients, dual CDN at 80% CHR each
Assume 5 TB clients on CDN A and 5 TB on CDN B, each at 0.80 CHR. Naïve fill ≈ 5×0.20 + 5×0.20 = 2 TB origin pull (before inflation). Run Mode C twice with origin $/GB Unknown until verified. Dual cold-start events can exceed this. Not a quote.
