Scaling desired state

Scale desired state by preserving bounded work and attributable evidence. The four-layer fold and pull-based convergence keep each machine’s work predictable; evidence volume tells you when to add the next lever. This makes growth an observed engineering decision tied to actual fleet pressure.

What stays bounded

• The four-layer fold resolves one machine’s state from a constant number of layers.
• Host-keyed journals, alerts, findings, and applied files give each machine one writer.
• Canary release keeps the changed-item blast radius tied to the canary wait.
• Jitter spreads scheduled runs across the cadence.

First breakpoint

Watch the evidence store first. Around 30 machines, long-lived journal data becomes the first meaningful repository cost because every machine carries the shared history. The recommended next build is signed journal compaction with a retention floor at the canary wait.

Later breakpoints

Add later levers when their pressure becomes visible. Around 75 machines, roster replay and the aggregate “which machines carry this item?” view become read-side costs. Around 50 simultaneous enrollments, batching roster additions reduces repeated publication work. Around 100 machines, per-group store sharding reduces shared-bookmark contention while preserving host-keyed evidence.

Design rules for the next tier

• Keep evidence paths independently attributable to their machine.
• Keep derived aggregate indexes out of apply decisions.
• Keep the canary window intact during compaction.
• Keep shard boundaries compatible with history-preserving projections.

Proof point

This operating model identifies evidence retention as the first breakpoint, gives journal compaction as the next build, and names sharding, aggregation, and batched enrollment as later levers. The sequence keeps each investment tied to observed fleet pressure.

machines=30 pressure=shared-history next=journal-compaction retention_floor=canary-wait
machines=75 pressure=roster-replay-and-aggregate-reads next=derived-index
machines=100 pressure=shared-bookmark-contention next=group-sharding