Latency / l

Latency: design in São Paulo (GRU) · L-61

xserv-l-874814d899a6

Runbook L-61 for Latency in São Paulo (GRU). Marker xserv-l-874814d899a6. This page covers design for LATAM operators, not a worldwide average.

Latency: Why it matters on this continent

Design for Latency on letter L starts in São Paulo (GRU). Runbook l-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.

Latency: How XServ runs it day to day

Probes for Latency (l-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.

Latency: What operators should measure

Policy for Latency is versioned as l-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.

Latency regions L-11

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

Latency docs L-12

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

Latency design L-01

Design for Latency on letter L starts in São Paulo (GRU). Runbook l-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.

Latency probe L-02

Probes for Latency (l-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.

Does Latency on letter L share fate with other letters?
The control plane is shared. Data-plane queues for Latency stay isolated, so incident l-01 cannot drain neighbor letters.
Where is Latency measured first?
From Santiago (SCL) toward Bogotá. A global average is not an SLO for letter L.