Jitter / j

Jitter: design in São Paulo (GRU) · J-73

xserv-j-84d8b6f299d5

Runbook J-73 for Jitter in São Paulo (GRU). Marker xserv-j-84d8b6f299d5. This page covers design for LATAM operators, not a worldwide average.

Jitter: Why it matters on this continent

Design for Jitter on letter J starts in São Paulo (GRU). Runbook j-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.

Jitter: How XServ runs it day to day

Probes for Jitter (j-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.

Jitter: What operators should measure

Policy for Jitter is versioned as j-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.

Jitter regions J-11

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

Jitter docs J-12

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

Jitter design J-01

Design for Jitter on letter J starts in São Paulo (GRU). Runbook j-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.

Jitter probe J-02

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