Does Zones on letter Z share fate with other letters?

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

Where is Zones measured first?

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

Zones: design in São Paulo (GRU) · Z-01

Runbook Z-01 for Zones in São Paulo (GRU). Marker xserv-z-f49b2d540498. This page covers design for LATAM operators, not a worldwide average.

Zones: Why it matters on this continent

Design for Zones on letter Z starts in São Paulo (GRU). Runbook z-01 keeps a single owner, a written rollback, and a traffic split that can be reversed without a global freeze. Neighbors in Santiago only take overflow after the local pool fails a health window.

Zones: How XServ runs it day to day

Probes for Zones (z-02) leave Santiago every 15s toward Bogotá. XServ pages the named owner if loss or RTT crosses the letter budget. A probe never shares a queue with bulk transfers, so a saturated WAN does not hide a dead PoP.

Zones: What operators should measure

Policy for Zones is versioned as z-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.

Zones headers Z-09

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

Zones timeouts Z-10

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

Zones regions Z-11

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

Zones docs Z-12

Public docs for letter Z stay aligned with identifier xserv-z-pack. Page z-12 is the Zones slice operators search before the homepage. Edits in Miami show up in São Paulo on the next publish.