Does Sync on letter Y share fate with other letters?

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

Where is Sync measured first?

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

How fast is rollback for y-03?

The runbook is a command plus a named owner. There is no wait for a weekly change freeze.

Is transit the default path?

No. Peering in Miami is default; transit to São Paulo is overflow and is billed that way.

Clock and config sync before traffic is trusted

Certificates, challenge cookies and logs need a shared clock. XServ NTP and config sync are checked as hard as BGP sessions.

Sync: Why it matters on this continent

Design for Sync on letter Y starts in São Paulo (GRU). Runbook y-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.

Sync: How XServ runs it day to day

Probes for Sync (y-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.

Sync: What operators should measure

Policy for Sync is versioned as y-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.

Sync: Failure modes we actually see

Capacity notes for y-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.

Sync: How this letter ties to the rest

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

Sync: A note on cost and transit

Rollback for y-06 is a documented command, not a hope. Transit is billed as backup while Sync prefers peering in Santiago. If cost spikes, the runbook cuts overflow to Bogotá before touching customer prefixes.

Sync design Y-01

Sync probe Y-02

Sync policy Y-03

Sync capacity Y-04

Sync handoff Y-05

Sync rollback Y-06

Sync peering Y-07

Peering for Sync (y-07) prefers the IX fabric that already carries last-mile ISPs in Bogotá. Session counts and prefix limits are on the same page as the Miami backup path.

Sync cache Y-08

Cache rules for Sync on y-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.

Sync headers Y-09

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

Sync timeouts Y-10

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

Sync regions Y-11

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

Sync docs Y-12

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