Does DNS on letter D share fate with other letters?

The control plane is shared. Data-plane queues for DNS stay isolated, so incident d-01 cannot drain neighbor letters.

Where is DNS measured first?

From Santiago (SCL) toward Bogotá. A global average is not an SLO for letter D.

DNS: headers in São Paulo (GRU) · D-09

Runbook D-09 for DNS in São Paulo (GRU). Marker xserv-d-e55b92c33146. This page covers headers for LATAM operators, not a worldwide average.

DNS: What operators should measure

Policy for DNS is versioned as d-03. Operators measure error rate, p95 from Bogotá, and time-to-rollback — not a worldwide average. Changes land in Bogotá first, then Miami, with a hold if either region regresses.

DNS: Failure modes we actually see

Capacity notes for d-04 assume rainy-season power in Miami and festival peaks toward São Paulo. The failure we actually see is a single uplink, not a cartoon partition of the whole continent. Spare ports and a second provider sit on the same runbook.

DNS: How this letter ties to the rest

Handoff from letter D DNS into the rest of the platform uses the same request IDs as the gateway. Runbook d-05 names who accepts the ticket after São Paulo pages out. Santiago does not silently inherit the incident.

DNS cache D-08

Cache rules for DNS on d-08 keep language-correct objects near Miami. São Paulo is a sibling cache, not an origin. TTLs are short enough that a bad asset does not live through a weekend.

DNS headers D-09

Headers for d-09 carry the letter, the region (GRU) and a request id. DNS debugging in São Paulo should not require a packet capture in Santiago first.

DNS timeouts D-10

Timeouts on d-10 are tighter than the WAN RTT to Bogotá. DNS in Santiago fails fast and retries once; a third try needs a human because it is no longer a blip.

DNS regions D-11

Region names on d-11 match DNS and tickets: Bogotá / BOG, with Miami as the documented pair. DNS dashboards never say “LATAM” as if it were one RTT.